Fingerstick Blood Research Articles

Pre-analytical conditions influencing analysis of folate in dried plasma microsamples

IntroductionDetermination of folate insufficiency is of considerable interest given its importance in fetal development and red blood cell formation; however, access to blood tests may be limited due to the requirement for phlebotomy as well as controlled temperature shipping of blood specimens to laboratories for testing due to the inherent instability of folate and its vitamers. MethodsAn LC-MS/MS test was developed and validated for the measurement of 5-methyltetrahydrofolate (5MTHF) in dried plasma specimens collected from fingerstick blood using a laminar flow blood separation device, as well as liquid venous plasma for comparison. Two pre-analytical factors investigated influencing the measurement of 5MTHF in dried plasma were hemolysis of the fingerstick blood during collection and storage/shipment of the dried plasma. ResultsAlthough observed infrequently, hemolysis >10 % resulted in elevated 5MTHF measurements, but hemolysis >1 % resulted in elevated chloride measurements, which were necessary to normalize 5MTHF measurements for variation in volume of dried plasma specimens. Stability of 5MTHF was improved in dried plasma relative to liquid plasma at ambient temperatures, but not sufficiently to allow for uncontrolled temperature shipping despite controlling for humidity and light exposure. Shipping studies emulating ISTA procedure 7D were conducted with a reusable cold packaging solution. The packaging failed to stabilize 5MTHF in dried plasma specimens during a 2-day summer shipping evaluation, but did provide sufficient temperature control to stabilize 5MTHF during the overnight shipping evaluation. ConclusionOur studies provide boundary conditions with respect to hemolysis, storage, and shipping for successful analysis of 5MTHF from dried plasma specimens.

Rapid, sensitive, and specific lateral-flow immunochromatographic point-of-care device for detection of varicella-zoster virus immunoglobulin G antibodies in fingerstick blood

Varicella zoster virus (VZV) causes childhood chickenpox, becomes latent in sensory ganglia and reactivates years later to cause shingles (Zoster) and postherpetic neuralgia in the elderly and immunosuppressed individuals. Serologic IgG tests can be used to determine if a person has antibodies to VZV from past varicella infection or had received varicella or zoster (shingles) vaccination. Commercial enzyme-linked immunosorbent assays (ELISAs) are currently used for the detection of VZV IgG antibodies in patient serum samples. However, ELISA tests require collection and processing of blood samples in a CLIA laboratory to separate serum or plasma for further testing. In this paper, we describe the development and testing of an antibody based Lateral Flow Immunochromatographic assay (LFA) device for the detection of VZV IgG in fingerstick whole blood. Analytical and clinical analyses were performed to compare the performance characteristics of the Viro VZV IgG LFA (VZV LFA) and the Diamedix VZV IgG ELISA. Analytical studies demonstrated the higher sensitivity of the VZV LFA compared to the ELISA by testing dilutions of the WHO VZV IgG serum International Standard. Clinical performance characteristics of the VZV LFA fingerstick whole blood assay were assessed at three point of care (POC) facilities by untrained users testing samples from 300 prospectively enrolled study subjects. VZV LFA results were compared with results obtained by testing serum samples obtained from the same study participants by the Diamedix VZV IgG ELISA. Two specimens with invalid results by the LFA assay were not included in the LFA performance calculations and nine equivocal ELISA results were included as positive for IgG results. The results from all three POC clinical sites demonstrated the higher sensitivity/positive percent agreement (PPA) (99.26%, 95% CI: 97.34–99.80) of the VZV LFA compared to the Diamedix VZV IgG ELISA (94.08%, 95% CI: 90.72–96.27). The specificity/negative percent agreement (NPA) of the VZV LFA compared to the ELISA test was calculated initially to be 39.29% (95% CI: 23.57–57.59) with 19 discordant test results out of 298 test results between the two assays (17 LFA positive/ELISA negative and two LFA negative/ELISA positive). The PPA and true NPA of the VZV LFA were determined by testing all 298 samples, including the discordant (19) and all concordant negative and positive (279) study subject serum samples, before and after blocking VZV gE antibody sites in the samples by spiking with VZV LFA gE capture antigen. The NPA improved to 100% (95% CI: 74.12–100) after the procedure when compared to the ELISA test results. The comparator ELISA PPA based on the spiking/blocking study remained as 94.08%, (95% CI: 90.72–96.27), comparable to test results from untreated samples.The VZV LFA has been demonstrated to be simple and sufficiently robust for use in CLIA-waived POC facilities by untrained healthcare professionals and to detect VZV IgG in 20 min from fingerstick whole blood. The VZV LFA therefore provides a fast, reliable, and highly sensitive method of determining prior VZV viral infection or varicella and zoster vaccination status.

Evaluation of SARS-CoV-2-Specific T-Cell Activation with a Rapid On-Chip IGRA.

Interferon-gamma release assays (IGRAs) that measure pathogen-specific T-cell response rates can provide a more reliable estimate of protection than specific antibody levels but have limited potential for widespread use due to their workflow, personnel, and instrumentation demands. The major vaccines for SARS-CoV-2 have demonstrated substantial efficacy against all of its current variants, but approaches are needed to determine how these vaccines will perform against future variants, as they arise, to inform vaccine and public health policies. Here we describe a rapid, sensitive, nanolayer polylysine-integrated microfluidic chip IGRA read by a fluorescent microscope that has a 5 h sample-to-answer time and uses ∼25 μL of a fingerstick whole blood sample. Results from this assay correlated with those of a comparable clinical IGRA when used to evaluate the T-cell response to SARS-CoV-2 peptides in a population of vaccinated and/or infected individuals. Notably, this streamlined and inexpensive assay is suitable for high-throughput analyses in resource-limited settings for other infectious diseases.

Estimation of Vitamin D Levels Using a Chairside Diagnostic Test Kit in Patients with Gingivitis and Periodontitis: A Cross-Sectional Study.

Periodontitis is an inflammatory condition of the periodontium that is instigated by microbial biofilms developed on the teeth. The purpose of the study was to ascertain the vitamin D status of gingivitis and periodontitis patients while maintaining a healthy group as the control using simple low-cost chairside pre-coated with 25-OH Vitamin D antigen rapid test kits. From outpatients visiting the college's periodontics clinics, a total of 101 patients were screened. The study sample includes 38 patients in the periodontitis group, 32 in the gingivitis group, and 31 in the healthy group. A middle-digit needle was used to collect blood samples, which were put into a test cassette with membrane that had been coated with 25-OH Vitamin D antigen on the test line area of the strip. Vitamin D Quick Test (Natejah) Semi-quantitatively detects 25-hydroxyvitamin D (25 (OH) D) in human finger-stick complete blood at a cutoff convergence of 30 ± 4 ng/mL. Vitamin D blood levels below 80 nmol/L are considered to have deficient vitamin 25(OH)D levels. Clinical parameters between healthy, gingivitis, and different stages of periodontitis subjects were compared using one-way ANOVA and Tukey's multiple comparison. Fisher's exact test was done to compare vitamin D levels in the three groups. Fisher's exact test revealed that there was a statistically significant increase in the number of subjects with stages 4 and stage 3 periodontitis who lacked vitamin D levels (less than 80 nmol/L). Whereas least deficient in Vit D were noticed among Healthy and Gingivitis subjects. When compared to healthy individuals, gingivitis, and various stages of periodontitis had significantly higher mean PI values in a Tukey's multiple comparison. Vitamin D deficiency was found to be 27.5% in subjects with gingivitis and 71.5% in subjects with periodontitis. Periodontitis is associated with vitamin D deficiency, in contrast to gingivitis and healthy subjects. The severity of periodontitis was likewise linked to the amount of vitamin D in the individual's blood. When compared to expensive, time-consuming, and laborious laboratory methods, the findings of this study suggest that a simple inexpensive chairside pre-coated with 25-OH Vitamin D antigen rapid test kits can be considered a viable alternative for determining vitamin D levels.

Nighttime hypoglycemia in Japanese children with type 1 diabetes mellitus treated with multiple daily injection insulin therapy.

Prevention of hypoglycemia is an important strategy for glycemic management in patients with type 1 diabetes mellitus (T1D). Hypoglycemia is difficult to recognize at night while sleeping, particularly when using multiple daily injection (MDI) insulin therapy rather than sensor-augmented insulin-pump therapy. Therefore, it is possible that patients with T1D are at higher risk of nocturnal hypoglycemia when insulin is administered using an MDI regimen. We investigated nocturnal hypoglycemia in 50 pediatric patients with T1D on MDI insulin therapy using data from an intermittently scanned continuous glucose monitoring (isCGM) system. Hypoglycemia was observed on 446 of the 1,270 nights studied. Most of the hypoglycemic episodes were severe (blood glucose <54 mg/dL). On nights when hypoglycemia occurred, the blood glucose concentrations measured using finger-stick blood glucose monitoring (FSGM) before sleep and the next morning were lower than nights when hypoglycemia did not occur. However, few values were below the normal blood glucose range, suggesting that FSGM alone may be insufficient to detect nocturnal hypoglycemia. Approximately 7% of time was spent below the normal glucose range during the 10 hours from 21:00 to 7:00 the next morning. This result suggests that the patients on MDI insulin therapy could end up spending more time in hypoglycemia than is recommended by the American Diabetes Association (time below range <4.0% of time per day). Monitoring glucose levels overnight using an isCGM sensor may improve glycemic management via automatic detection of blood glucose peaks and troughs.

Evaluation of the Performance Characteristics for SARS-CoV-2 S-RBD IgG Antibody Rapid Test Cassette (Fingerstick Whole Blood) by Comparing CLIA Test

Background: SARS-CoV-2, a branch of coronavirus, is a positive-strand RNA virus with four major proteins and several auxiliary proteins wrapped with genetic material. It mediates the invasion of the virus mainly through the binding of the S protein to host cell receptors and determines the organization of virus and host tropism. Human coronaviruses are one of the fastest-developing viruses due to their high genomic nucleotide substitution rate and recombination ability. Human coronaviruses are associated with a variety of respiratory diseases of varying severity, such as colds, pneumonia, and bronchitis. On January 30 2020, the World Health Organization (WHO) declared that the COVID-19 outbreak caused by SARS-CoV2 constituted a public health emergency of international concern (PHEIC) and characterized as a pandemic on March 11 2020. In an effort to expedite the availability of in vitro diagnostics (IVDs) needed in public health emergencies, the WHO has opened the development of an emergency use checklist process, which aims to assist procurement agencies and Member States in deciding whether a specific IVD is suitable for use based on a minimum set of available quality, safety and performance data. IVDs with guaranteed quality, safety and performance are a key component of the overall strategy to control the pandemic.Objective: The main purpose of this evaluation report is to investigate the sensitivity of the SARS-CoV-2 S-RBD IgG Antibody Rapid Test (Fingerstick Whole Blood) for diagnosis during COVID-19. Method: The SARS-CoV-2 S-RBD IgG Antibody Rapid Test (Fingerstick Whole Blood) is a rapid chromatographic immunoassay intended for the qualitative detection of IgG antibodies to SARS-CoV-2 spike (S) protein receptor binding domain (RBD) in human fingerstick whole blood approximately 10 days after vaccination. Result: Through the clinical evaluation of vaccinated, unvaccinated, and virus-uninfected populations, the results show that the overall relative sensitivity of SARS-CoV-2 S-RBD IgG Antibody Rapid Test (Fingerstick Whole Blood) is 97.7%, the relative specificity is 99.0%, and the relative accuracy is 98.5%. Conclusion: CITEST SARS-CoV-2 S-RBD IgG Antibody Rapid Test (Fingerstick Whole Blood) is a rapid test that is a qualitative membrane-based immunoassay intended to detect IgG antibodies to SARS-CoV-2 spike (S) protein receptor binding domain (RBD) in fingerstick whole blood. The product is simple to operate and has been validated against an industry leading commercial CLIA test to give results within 10 minutes of the sample being tested. A comparison of 1257 samples showed an accuracy of 98.5% and an excellent sensitivity of 97.7%. People can use the test kits to get accurate results and determine if they have antibodies in their bodies after they have been vaccinated.

1931. Antibodies to SARS-CoV-2 in a Medical School Department of Pediatrics

Abstract Background Healthcare workers are at high risk of Covid-19 (C19) infection and received priority for C19 vaccinations. Therefore, we conducted a serosurvey to determine anti-C19 antibodies and evidence of C19 infection in health care employees who did or did not have direct contact with patients. Methods 49 participants provided finger stick blood samples collected onto filter papers and tested for antibodies to C19 using Bio-Plex Pro Human SARS-CoV-2 IgG reagents. Antibodies to C19 nucleocapsid (N), receptor-binding domain (RBD), spike 1 (S1), and spike 2 (S2) were measured. Samples were collected 8 to 11 months after C19 vaccines were made available. Results All participants received two doses of Pfizer BioNTech or Moderna RNA-based C19 vaccines, and all showed serological evidence of antibodies to C19 RBD, S1, and S2. Antibodies to N, considered a marker of C19 infection, were detected in 16 individuals, of whom 10 reported having a PCR documented C19 infections. 6 individuals had evidence of C19 infection of which they were not aware. Antibody levels were notably higher following infection and for not infected participants following Pfizer-BioNTech vaccination. There was a 20% higher infection rate in participants with direct patient contact. Conclusion This vaccinated population had significant rates of strong antibody responses to C19 infection and a notable rate of C19 infections, most notable in those providing direct patient care. Disclosures All Authors: No reported disclosures.

A Highly Sensitive Immunoassay for Determination of Immune Response to SARS-CoV-2 in Capillary Blood Samples.

Throughout the pandemic, serological assays have been revealed as crucial for detecting previous exposures to the virus and determining the timing of antibody maintenance after vaccination or natural infection. This study aimed to develop an optimized enzyme-linked immunosorbent assay (ELISA)-based serology, which could be used in case of reagent shortages, such as that occurred in the beginning of this health emergency. As a result, we present a high-sensitive immunoassay for the determination of IgG levels in venous serum samples, using 2 μg/mL antigen (receptor-binding domain of the spike protein S1) for coating the plate and utilizing human samples at a dilution 1:1000. This method showed non-inferiority features versus a commercial kit, is less expensive, and has a higher spectrophotometric range that allows for a better quantification of the antibody titers. The optical density values before and after heating venous serum samples at 56 °C during 30 min was quite similar, showing that heat inactivation can be used to reduce the biohazardous risks while handling samples. Furthermore, we show that finger-stick capillary blood samples can also serve as a suitable source for IgG detection, bypassing the need for serum isolation and being suitable for point-of-care application (Pearson's coefficient correlation with capillary serum was 0.95, being statistically significant).

Evaluation of Bio-Rad D100 for HbA1c testing of dried blood spot samples

Abstract Hemoglobin A1c (HbA1c) testing is critical for diabetes diagnosis and monitoring. Although many studies have demonstrated the feasibility of measuring HbA1c from dried blood spots (DBS) using immunoassays, enzymatic assays, and certain high-performance liquid chromatography (HPLC) assays, there is limited evidence supporting the use of the Bio-Rad D100 HPLC method. We evaluated the feasibility of testing HbA1c from DBS using Bio-Rad D100 to support the assessment of glycemic control for the growing field of telehealth. Deidentified residual EDTA whole blood samples were processed, and HbA1c was measured on the Bio-Rad D100 on day zero. Concurrently, DBS were prepared for each sample by spotting 50 µL of blood onto a Whatman® 903 filter paper. The samples were dried overnight and stored at room temperature for two days. On day 2, a DBS disc with a diameter of 3.2 mm was eluted with 4.5 mL of Bio-Rad diluent for 20 minutes. The supernatants of the DBS samples were then processed on the platform. HbA1c values from the DBS samples were compared to the EDTA whole blood results. Compared to the EDTA samples, the HbA1c concentrations of the corresponding DBS samples were elevated, especially for samples with original results less than 7.0%. Furthermore, the chromatograms of the DBS samples were significantly altered; we observed baseline elevation and the appearance of unknown minor peaks. This issue was investigated. First, blank DBS samples were created by directly spotting filter paper with diluent or adding diluent into an empty EDTA tube and then spotting the filter paper with the mixture of diluent and EDTA. The blank DBS samples were tested, and the lack of peaks suggested that the interference was not from the diluent, EDTA, or the filter paper. DBS samples were also prepared with sodium heparin whole blood, finger-stick capillary blood, and multiple brands of filter papers and tested using a different HPLC method. However, the interference was still present in those samples, indicating the interference is most likely due to the time-dependent degradation of the samples themselves. Of note, the alternate HPLC method showed less chromatogram alteration. To prevent possible adduct formation, DBS samples were eluted in the presence of various concentrations of cysteine (Jeppsson et al. 1986). However, the pretreatment did not eliminate the chromatogram changes. Finally, a multiple regression model was created using the results of day two A1c, A0, and F peaks, and a correction factor was generated. The corrected HbA1c concentrations were well within +/-6% of the initial HbA1c concentrations. In conclusion, the Bio-Rad D100 HPLC method appears particularly susceptible to stability changes in DBS samples, and further analysis is needed before employing a correction factor.

Abstract 15313: Hypoglycemia: The Forgotten "H&amp;T" in Cardiac Arrest

Introduction: Hypoglycemia is known to cause cardiac arrhythmias and even sudden cardiac death by inducing oxidative stress, QT prolongation, and myocardial injury. Chromosomal deletion of 1p36 is associated with learning difficulty, progressive renal disease, and cardiomyopathy. To our knowledge, this is the first case of a patient with 1p36 deletion syndrome and end-stage renal disease (ESRD) who developed cardiac arrest due to hypoglycemia. Case Presentation: A 26-year-old female presented to the emergency department with generalized itching, weakness, and progressive dyspnea after missing multiple hemodialysis (HD) sessions. She was admitted for HD and her stay was complicated by an episode of coffee-ground emesis and she was nil per oral (NPO) for an endoscopy. That night, the patient became bradycardic and had a cardiac arrest with pulseless electrical activity (PEA). Fingerstick blood glucose was undetectable during resuscitation and ROSC was achieved instantaneously after dextrose administration. The patient had no history of diabetes and was refusing glucose checks while NPO. She had a remarkable neurological recovery post-cardiac arrest. However, her glucose levels remained persistently low despite maximally tolerated feeds. An extensive workup for persistent hypoglycemia including peptide C levels, hba1c, and insulin level were within normal limits. Her cortisol level was appropriately raised. CT scan of the head performed was normal. Cardiac catheterization revealed no coronary artery disease. Discussions: Hypoglycemia was removed from the Advanced Cardiovascular Life Support (ACLS) algorithm as a reversible cause of cardiac arrest in 2010. Our case is a reminder of a life-threatening yet quickly reversible cause of cardiac arrest. Conclusions: ESRD increases the risk of hypoglycemia due to decreased insulin clearance and must be carefully monitored while NPO. Physicians have to be aware that routine dextrose administration during cardiac resuscitation does not improve survival and neurological outcomes.

ODP157 A Case of Pancreatic Insulinoma With Hypoglycemia Unawareneness

Abstract Clinical Case An 84-year-old woman with hypertension, type 2 diabetes, and a history of frequent falls, presented to the hospital after one week of recurrent falls with progressive worsening right-sided weakness, speech difficulties, and urinary incontinence. She was found to have a 2.8cm subacute subdural hematoma with midline shift and underwent successful subdural evacuation placement, nevertheless, her course was complicated by asymptomatic hypoglycemia. During her prolonged hospitalization, she experienced a 15-pound weight loss, initially attributed to poor oral intake. She was previously on glimepiride for her diabetes but this was discontinued about two months prior for low sugars. The patient did not meet Whipple's triad, as she denied symptoms of hypoglycemia and felt no different once her glucoses normalized. However, nursing staff noticed a slight difference in her cognition and behavior during these hypoglycemic episodes, which improved after correction. Laboratory testing: A fasting protocol was initiated. After seven hours, her finger stick blood glucose dropped to 42 mg/dL. Her Insulin 23.8 uU/mL (1.9-23), Proinsulin 46.9 pmol/L (&amp;lt;10), and C-peptide 5.3 ng/mL (0.9-7.1) were relatively high at this time, despite a confirmed low plasma glucose of 47 mg/dL. Beta-hydroxybutyrate was 0.24 mmol/L (&amp;lt;0.3) with Hemoglobin 16.5 G/dL (11.7-15),and HbA1c 5.6%. Her blood glucoseimproved to 126 mg/dL after administration of 1mg glucagon. Anti-Insulin antibody &amp;lt;5 uU/mL and a sulfonylurea screen were negative. The fasting protocol was discontinued and she was started on Dextrose 10% infusion, then transitioned to diazoxide. A dedicated MRI of the abdomen did not demonstrate any pancreatic lesions. An esophagogastroduodenoscopy was then performed, revealing a 12-mm mass in the head/uncinate of the pancreatic body. FNA confirmeda low-grade, well-differentiated neuroendocrine tumor. Immunohistochemical stains were positive for Insulin and Synaptophysin, and negative for Chromogranin, supporting the diagnosis of insulinoma. Endoscopic ultrasound with successful ethanol ablation was completed. Subsequently, her hypoglycemia rapidly improved off treatment. Conclusion Per the 2009 Endocrine Society guidelines, evaluation of recurrent low blood sugar is only recommended if Whipple's triad is present. However, this case highlights that hypoglycemia unawareness can mask Whipple's triad. It is not unusual for patients with longstanding hypoglycemia to lose neurogenic and neuroglycopenic symptoms. This can complicate and delay the diagnosis of insulinoma, as it did in this patient with multiple falls. Her documented weight loss, decreased oral intake, and relatively high HbA1c are not classic of insulinoma and were further obstacles for diagnosis. Endocrine guidelines should incorporate the importance of hypoglycemia unawareness into its algorithm. In this setting, we should consider a lower threshold to initiate fasting protocol and biochemical testing during a hypoglycemic event (&amp;lt;55mg/dL). Presentation: No date and time listed

RF15 | PMON304 Utilizing LC-MS/MS for the clinical quantitation of testosterone using dried blood spot and how it compare to serum

Abstract Introduction Hormones are the chemical messengers of your body. Steroid hormones like testosterone are a specific class of hormone that are produced predominantly in the gonads (sex steroids) and less so in the adrenal glands (corticosteroids). When too little or too much of testosterone is produced, adverse symptoms and conditions can occur. In order to restore the vital balance of hormones, detailed and accurate measurement of hormones is needed. Serum currently represents the gold standard when it comes to hormone testing. However, there are other body fluids such as saliva, urine, and capillary blood (finger prick) where the hormone levels correlate well with serum. A significant advantage of these alternative fluids is that they are non-invasive, or semi-invasive, can be collected "on the go" by the patient at home, and don't have the strict requirements for cold-chain shipping. Objectives The primary objective of this work is to show that finger-prick dried blood spot blood is quantitatively equivalent to serum when compared by LC-MS/MS testing in patients only producing endogenous testosterone. We will also show that topically delivered testosterone increases in a dose-dependent fashion, whereas serum levels of testosterone increase very little regardless of topical testosterone dosing. Methods Serum samples were collected by a physician and sent into the lab and analyzed for testosterone on a Siemens Immulite 2000 autoanalyzer. Dried blood spots were collected by the patient and sent into the lab and analyzed on an AB Sciex 5500 triple quadrupole mass spectrometer. Results Patients who don't supplement with topical testosterone show a strong correlation between endogenous venipuncture serum and DBS testosterone levels. In sharp contrast, samples from topical testosterone users show remarkably different results with hormone levels 10-100×higher in the DBS than serum results. Conclusion These results are significant because it gives a glimpse into which forms of testing are most appropriate for different patients based on the mode of steroid hormone delivery. Without using the proper body fluid for testosterone detection, patients potentially could be overdosed if serum results are used to guide therapeutic dosing. Also, venipuncture serum will fail to show "sports-doping" with exogenous testosterone, which easily can be identified with capillary finger stick blood. This is also significant as the World Anti-doping Agency has finally begun accepting these data as fact and have listed dried blood spot as an appropriate form of collection and analysis for drug testing. This can help find athletes using performance enhancers that would normally have skirted by the system (1). WADA. (2021, May 21) WADA Executive Committee approves Technical Document for innovative dried blood spot testing method. https://www.wada-ama.org/en/media/news/wada-executive-committee-approves-technical-document-for-innovative-dried-blood-spot. Presentation: Sunday, June 12, 2022 12:36 p.m. - 12:41 p.m., Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

ODP208 Hypoglycemia as a Presenting Feature of McArdle's Disease

Abstract Introduction McArdle's disease (glycogen storage disease type V) is an autosomal recessive disease caused by mutations in the gene encoding for the muscle isoform of glycogen phosphorylase (PYGM). Characteristic symptoms include exercise intolerance, myalgia, muscle stiffness. Approximately half develop rhabdomyolysis, myoglobinuria, and renal failure. Hypoglycemia is an uncommon presenting symptom. Case report A 36-year-old male, previous college football athlete presented with jitteriness and blurry vision while exercising over the last one year. Symptoms occur 12-15 minutes into aerobic exercise. Fingerstick blood sugar during these episodes were as low as 30 mg/dl and afterwards the patient reported fatigue all day long. Consuming high carbohydrate foods and fluids supplemented with dextrose prior to exercise mitigate his symptoms. He reported no fasting hypoglycemia. Retrospectively, the patient reports that for years he noticed feeling fatigued a few minutes into starting exerice which improves after short periods of rest "second wind phenomenon." He can perform heavy resistance exercise like weightlifting but struggles with sustained aerobic activity. Past medical history is significant for HLA B27 positivity, alopecia areata and uveitis. Medications include multivitamin and creatine supplements. Physical exam revealed a healthy, well developed muscular individual with no other remarkable findings. Family history is significant for McArdle's disease in his brother, diagnosed at age 20 based on a muscle biopsy after multiple episodes of rhabdomyolysis. Grandfather had diabetes mellitus and pancreatic carcinoma. Labs revealed a creatine kinase (CK) level of 1638.7 U/L (49-397 U/L), CK-MB 49.1 ((0.1-5.9 ng/ml), 8 AM morning cortisol of 12.3 ug/dl (4.2-22.4 ug/dl), A1c 5.3%. There was no myoglobinuria. Thyroid function tests were within normal limits. Investigations done during an episode of exercise induced hypoglycemia - fingerstick blood sugar 44 mg/dl, plasma blood glucose 56 mg/dl(65-99 mg/dl), Insulin &amp;lt;0.5 mU/L(3-25mU/l), C-Peptide 0.5ng/ml(1.1-4.4ng/ml), Proinsulin 1.1 pmol/L(0-10. 0 pmol/L). Insulin autoantibody was negative. This ruled out exercise induced hyperinsulinemia. IGF-1 and IGF-2 levels were normal. Genetic study performed by the Glycogen Storage Disease Panel showed PYGM c.2262del (p. Lys754Asnfs*49), Pathogenic, PYGM c.1537A&amp;gt;G (p. Ile513Val), Uncertain Significance, PYGM c.833G&amp;gt;C (p. Arg278Pro), Uncertain Significance. Subsequently, the patient's brother underwent genetic testing, which confirmed the presence of all three before-mentioned PYGM variants. His father was found to carry the two variants of undetermined significance, suggesting that the patient and his brother inherited the pathogenic variant from their deceased mother. Discussion The patient's medical history, along with his personal and family's genetic findings were found to be consistent with McArdle's disease. Our patient's presentation is unique in that his exercise tolerance is much higher as compared to most individuals with McArdle's and his presenting complaint was hypoglycemia. Additionally, one of the variants of uncertain significance is likely to be recognized as pathogenic in the future. Presentation: No date and time listed

LBODP061 A Pilot Trial Of Continuous Glucose Monitoring Technology In The Perioperative Period

Abstract Objective To evaluate use of continuous glucose monitoring (CGM) technology in the perioperative setting by comparing CGM with concurrent point of care fingerstick blood glucose (BG) or arterial BG values, as indicated, in patients with hyperglycemia and/or diabetes mellitus undergoing surgery. To assess if grounding device correlated with loss of CGM signal as a prior study of CGM in the perioperative period noted intermittent signal loss during operative time. Methods A prospective cohort analysis of 94 participants with hyperglycemia and/or diabetes mellitus undergoing surgery of 3 hours duration was conducted using Dexcom G6 and/or Freestyle Libre 2. 0 CGM. CGMs were placed preoperatively and compared to standard of care BG checks in the perioperative setting. Correction insulin was administered based on fingerstick glucoses. Of those consented, 18 were excluded resulting in 76 enrolled subjects. Results Preliminary data for use of CGM in perioperative period analyzed 50 participants with Freestyle Libre 2. 0 CGM, 20 participants with Dexcom G6 CGM, and 6 participants with both devices worn simultaneously. Lost sensor data occurred for 3 participants wearing Dexcom G6 CGM and 10 participants wearing Freestyle Libre 2. 0 CGM, which affected 2 of the participants wearing both devices simultaneously. The absolute difference of Dexcom G6 CGM glucose readings compared to BG readings was 29.17 mg/dL (SD = 22.15). The absolute difference of Freestyle Libre 2. 0 CGM glucose readings compared to BG readings was 26.94 mg/dL (SD = 24.16). There was not a significant difference in averages of absolute change in glucose when comparing Dexcom G6 CGM to Freestyle Libre 2. 0 CGM when utilized simultaneously. Grounding devices utilized Megadyne grounding pad for use of bipolar cautery, monopolar cautery, and surgeries with da Vinci robot. Of the 13 participants with lost data, 3 patients had bipolar cautery reported as being used at least once and 10 participants with lost data utilized monopolar cautery. None of the 6 participants with surgery utilizing da Vinci robot had loss of CGM data. Conclusion Both Dexcom G6 and Freestyle Libre 2. 0 CGMs were able to be utilized in the perioperative setting and generally functioned well. Use of CGM provided more glycemic data and better characterized glycemic trends than individual BG readings. It is anticipated that this technology could improve prevention of hypoglycemic events and better glycemic control in the perioperative setting. Use of CGMs in the perioperative setting is a novel area of application that warrants further evaluation of this technology. Presentation: No date and time listed

Autoimmune gene expression profiling of fingerstick whole blood in Chronic Fatigue Syndrome

BackgroundMyalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a debilitating condition that can lead to severe impairment of physical, psychological, cognitive, social, and occupational functions. The cause of ME/CFS remains incompletely understood. There is no clinical diagnostic test for ME/CFS. Although many therapies have been used off-label to manage symptoms of ME/CFS, there are limited, if any, specific therapies or cure for ME/CFS. In this study, we investigated the expression of genes specific to key immune functions, and viral infection status in ME/CFS patients with an aim of identifying biomarkers for characterization and/or treatment of the disease.MethodsIn 2021, one-hundred and sixty-six (166) patients diagnosed with ME/CFS and 83 healthy controls in the US participated in this study via a social media-based application (app). The patients and heathy volunteers consented to the study and provided self-collected finger-stick blood and first morning void urine samples from home. RNA from the fingerstick blood was tested using DxTerity’s 51-gene autoimmune RNA expression panel (AIP). In addition, DNA from the same fingerstick blood sample was extracted to detect viral load of 4 known ME/CFS associated viruses (HHV6, HHV7, CMV and EBV) using a real-time PCR method.ResultsAmong the 166 ME/CFS participants in the study, approximately half (49%) of the ME/CFS patients reported being house-bound or bedridden due to severe symptoms of the disease. From the AIP testing, ME/CFS patients with severe, bedridden conditions displayed significant increases in gene expression of IKZF2, IKZF3, HSPA8, BACH2, ABCE1 and CD3D, as compared to patients with mild to moderate disease conditions. These six aforementioned genes were further upregulated in the 22 bedridden participants who suffer not only from ME/CFS but also from other autoimmune diseases. These genes are involved in T cell, B cell and autoimmunity functions. Furthermore, IKZF3 (Aiolos) and IKZF2 (Helios), and BACH2 have been implicated in other autoimmune diseases such as systemic lupus erythematosus (SLE) and Rheumatoid Arthritis (RA). Among the 240 participants tested with the viral assays, 9 samples showed positive results (including 1 EBV positive and 8 HHV6 positives).ConclusionsOur study indicates that gene expression biomarkers may be used in identifying or differentiating subsets of ME/CFS patients having different levels of disease severity. These gene targets may also represent opportunities for new therapeutic modalities for the treatment of ME/CFS. The use of social media engaged patient recruitment and at-home sample collection represents a novel approach for conducting clinical research which saves cost, time and eliminates travel for office visits.

Diagnostic Accuracy of a Bacterial and Viral Biomarker Point-of-Care Test in the Outpatient Setting

Acute respiratory infections (ARIs) account for most outpatient visits. Discriminating bacterial vs viral etiology is a diagnostic challenge with therapeutic implications. To investigate whether FebriDx, a rapid, point-of-care immunoassay, can differentiate bacterial- from viral-associated host immune response in ARI through measurement of myxovirus resistance protein A (MxA) and C-reactive protein (CRP) from finger-stick blood. This diagnostic study enrolled adults and children who were symptomatic for ARI and individuals in a control group who were asymptomatic between October 2019 and April 2021. Included participants were a convenience sample of patients in outpatient settings (ie, emergency department, urgent care, and primary care) who were symptomatic, aged 1 year or older, and had suspected ARI and fever within 72 hours. Individuals with immunocompromised state and recent vaccine, antibiotics, stroke, surgery, major burn, or myocardial infarction were excluded. Of 1685 individuals assessed for eligibility, 259 individuals declined participation, 718 individuals were excluded, and 708 individuals were enrolled (520 patients with ARI, 170 patients without ARI, and 18 individuals who dropped out). Bacterial and viral immunoassay testing was performed using finger-stick blood. Results were read at 10 minutes, and treating clinicians and adjudicators were blinded to results. Bacterial- or viral-associated systemic host response to an ARI as determined by a predefined comparator algorithm with adjudication classified infection etiology. Among 520 participants with ARI (230 male patients [44.2%] and 290 female patients [55.8%]; mean [SD] age, 35.3 [17.7] years), 24 participants with missing laboratory information were classified as unknown (4.6%). Among 496 participants with a final diagnosis, 73 individuals (14.7%) were classified as having a bacterial-associated response, 296 individuals (59.7%) as having a viral-associated response, and 127 individuals (25.6%) as negative by the reference standard. The bacterial and viral test correctly classified 68 of 73 bacterial infections, demonstrating a sensitivity of 93.2% (95% CI, 84.9%-97.0%), specificity of 374 of 423 participants (88.4% [95% CI, 85.0%-91.1%]), positive predictive value (PPV) of 68 of 117 participants (58.1% [95% CI, 49.1%-66.7%), and negative predictive value (NPV) of 374 of 379 participants (98.7% [95% CI, 96.9%-99.4%]).The test correctly classified 208 of 296 viral infections, for a sensitivity of 70.3% (95% CI, 64.8%-75.2%), a specificity of 176 of 200 participants (88.0% [95% CI, 82.8%-91.8%]), a PPV of 208 of 232 participants (89.7% [95% CI, 85.1%-92.9%]), and an NPV of 176 of 264 participants (66.7% [95% CI, 60.8%-72.1%]). In this study, a rapid diagnostic test demonstrated diagnostic performance that may inform clinicians when assessing for bacterial or viral etiology of ARI symptoms.

Literature Highlights.

Literature Highlights is a digest of notable papers recently published in the leading respiratory journals, allowing our readers to stay up-to-date with research advances. This month we include coverage on use of monoclonal antibodies for prevention of COVID-19, acoustic epidemiology and cough assessment; immunotherapeutic interventions for viral and bacterial infections; the potential for harmful use of dexamethasone in COVID-19 patients; diagnostic accuracy of a new finger stick blood test for TB; Clinical standards for pulmonary TB.

Discordance between postprandial plasma glucose measurement and continuous glucose monitoring

There has been growing interest in studying postprandial glucose responses using continuous glucose monitoring (CGM) in nondiabetic individuals. Accurate measurement of glucose responses to meals can facilitate applications such as precision nutrition and early detection of diabetes. We aimed to quantify the discordance between simultaneous postprandial glucose measurements made using plasma and CGM. We studied 10 nondiabetic older adults who randomly consumed 9 predefined meals of varying macronutrient compositions. Glucose was measured for 8 h after the meal by the CGM, blood samples for plasma collection were taken regularly, and plasma glucose was quantified using gold-standard laboratory measurement and a fingerstick blood glucose meter. The primary outcome measured was the mean absolute relative difference (MARD) of CGM and fingerstick measurements relative to the gold standard. Secondary outcomes were Bland-Altman statistics, Clarke Error Grid, and time in range metrics. Additional subgroup analyses were performed by stratifying the postprandial glucose measurements based on the macronutrient composition of the meals. When compared against the gold-standard postprandial glucose measurements, the fingerstick meter was more accurate (MARD: 8.0%; 95% CI: 7.6%, 8.6%) than the CGM (MARD: 13.7%; 95% CI: 13.1%, 14.3%; P<0.0001). After the meals, Bland-Altman analysis demonstrated that the CGM underestimated the 8-h gold-standard glucose rise by 12.8mg/dL on average (P<0.0001), whereas the fingerstick meter did so by 5.5mg/dL on average (P<0.0001). The CGM underestimated the time spent in the 70-180mg/dL range (P=0.002) and overestimated the time spent <70mg/dL (P<0.0001) compared with the other 2 methods. We discovered discordance between gold standard, fingerstick, and CGM in measuring plasma glucose concentrations after a meal. Consequently, emerging applications of CGM in healthy individuals, such as precision nutrition and diabetes onset prediction, may need to account for these discordances.This trial was registered at clinicaltrials.gov as NCT04928872.

Perceptions and Experiences of Returning Self-collected Specimens for HIV, Bacterial STI and Potential PrEP Adherence Testing among Sexual Minority Men in the United States.

Few studies among gay, bisexual and other men who have sex with men (GBMSM) have examined facilitators and barriers to self-collecting specimens for extragenital STI screening, and none have evaluated attitudes towards self-collecting hair samples that can be utilized for PrEP drug level testing to assess adherence. To address this gap, we interviewed 25 sexually active GBMSM who were offered a choice to self-collect and return finger-stick blood samples (for actual HIV testing), pharyngeal swabs, rectal swabs and urine specimens (for actual gonorrhea and chlamydia testing), and hair samples (to visually determine their adequacy for PrEP drug level testing): 11 who returned all, 4 who returned some, and 10 who did not return any. Participants found self-collecting finger-stick blood samples and rectal swabs more challenging than other specimens. Frequently discussed facilitators of return included an opportunity to confirm one’s HIV or STI status, limited access to a healthcare provider and a desire to advance research focusing on home-based testing. Commonly cited barriers to return included low self-efficacy pertaining to self-collection and apprehension around the possibility of delay or loss of specimens during transit. Offering additional support such as real-time video conferencing may prove helpful in future field-based research with GBMSM.

Rapid Evaluation of Vaccine Booster Effectiveness against SARS-CoV-2 Variants.

ABSTRACTAs the COVID-19 pandemic continues, countries around the world are switching toward vaccinations and boosters to combat the pandemic. However, waning immunity against SARS-CoV-2 wild-type (WT) and variants have been widely reported. Booster vaccinations have shown to be able to increase immunological protection against new variants; however, the protection observed appears to decrease quickly over time suggesting a second booster shot may be appropriate. Moreover, heterogeneity and waning of the immune response at the individual level was observed suggesting a more personalized vaccination approach should be considered. To evaluate such a personalized strategy, it is important to have the ability to rapidly evaluate the level of neutralizing antibody (nAbs) response against variants at the individual level and ideally at a point of care setting. Here, we applied the recently developed cellulose pulled-down virus neutralization test (cpVNT) to rapidly assess individual nAb levels to WT and variants of concerns in response to booster vaccination. Our findings confirmed significant heterogeneity of nAb responses against a panel of SARS-CoV-2 variants, and indicated a strong increase in nAb response against variants of concern (VOCs) upon booster vaccination. For instance, the nAb response against current predominant omicron variant was observed with medians of 88.1% (n = 6, 95% CI = 73.2% to 96.2%) within 1-month postbooster and 70.7% (n = 22, 95% CI = 66.4% to 81.8%) 3 months postbooster. Our data show a point of care (POC) test focusing on nAb response levels against VOCs can guide decisions on the potential need for booster vaccinations at individual level. Importantly, it also suggests the current booster vaccines only give a transient protective response against some VOC and new more targeted formulations of a booster vaccine against specific VOC may need to be developed in the future.IMPORTANCE Vaccination against SARS-CoV-2 induces protection through production of neutralization antibodies (nAb). The level of nAb is a major indicator of immunity against SARS-CoV-2 infection. We developed a rapid point-of-care test that can monitor the nAb level from a drop of finger stick blood. Here, we have implemented the test to monitor individual nAb level against wild-type and variants of SARS-CoV-2 at various time points of vaccination, including post-second-dose vaccination and postbooster vaccination. Huge diversity of nAb levels were observed among individuals as well as increment in nAb levels especially against Omicron variant after booster vaccination. This study evaluated the performance of this point-of-care test for personalized nAb response tracking. It verifies the potential of using a rapid nAb test to guide future vaccination regimens at both the individual and population level.