Abbott Architect Research Articles

Performance of the Abbott Architect Immuno-Chemiluminometric NT-proBNP Assay.

Background: We evaluated the performance of the Abbott N-terminal pro-brain natriuretic peptide (NT-proBNP) assay against the Roche NT-proBNP immunoassay across two sites. Methods: Precision, linearity, and sensitivity studies were performed. A combined method of comparison and regression analysis was performed between the Roche and Abbott assays using samples from both sites (n = 494). To verify biotin interference, lyophilised biotin powder was reconstituted and spiked into serum samples at two medical decision levels (final concentration 500/4250 ng/mL) and compared to controls. NT-proBNP was also measured in anonymised leftover sera (n = 388) in a cardio-renal healthy population and stratified into three age bands—<50 (n = 145), 50–75 (n = 183) and >75 (n = 60). Results: Between-run precision (CV%) for NT-proBNP was 4.17/4.50 (139.5/142.0 pg/mL), 3.83/2.17 (521.6/506.3), and 4.60/2.51 (5053/4973), respectively. The assay was linear from 0.7–41,501 pg/mL. The limit of blank/quantitation was 1.2/7.9 pg/mL. The assay showed no interference from biotin up to 4250 ng/mL. Passing–Bablok regression analysis showed excellent agreement between the two assays (r = 0.999, 95% CI 0.999 to 0.999, p < 0.0001). The Roche assay had a slightly persistent, negative bias across different levels of NT-proBNP. ESC age cut-offs for diagnosing acute heart failure are applicable for the Abbott assay, with the median NT-proBNP of subjects < 50 years old at 43.0 pg/mL (range 4.9–456 pg/mL), 50–75 years old at 95.1 pg/mL (range 10.5–1079 pg/mL), and >75 years old at 173.1 pg/mL (range 23.2–1948 pg/mL). Conclusions: The Abbott Architect NT-proBNP assay has good performance that agrees with the manufacturer’s specifications. ESC/AHA recommended NT-proBNP age groups for acute heart failure diagnosis are applicable to this assay.

Prescreening with a Rapid Diagnostic Test Followed by a Confirmatory Qualitative Nucleic Acid Test Can Simplify Hepatitis C Diagnosis.

Asymptomatic hepatitis C virus (HCV) infection without treatment is associated with chronic liver diseases including hepatocellular carcinoma. A major obstacle to hepatitis C diagnosis leading to antiviral treatment in some developing countries is the complicated HCV testing required before treatment. To simplify an HCV test-to-treat strategy, which could lead to timely diagnosis and treatment at the point-of-care, we evaluated the performance of four anti-HCV rapid diagnostic tests (RDTs) (Abon, Blue Cross, Healgen, and SD Bioline). They yielded comparable sensitivity (80-83%), specificity (99-100%), and accuracy (90-91.5%). When we field-tested Abon in 4,769 residents of an HCV-endemic province in Thailand, 306 seropositive individuals (6.4%) were identified. In comparison, laboratory test using an automated commercial chemiluminescent microparticle immunoassay (Abbott ARCHITECT) identified slightly more seropositives (327% or 6.9%). Field implementation suggests that Abon was sensitive (88.7%), specific (99.6%), and accurate (98.9%). Furthermore, 82% (250/306) of Abon-positive samples had detectable HCV RNA as determined by nucleic acid test (Roche cobas). The same 250 samples out of 327 reactive in Abbott immunoassay also had detectable HCV RNA (mean RNA level: log 6.28 IU/mL, range: log 3.06- 7.78 IU/mL). The use of RDT followed by qualitative nucleic acid test can cost-effectively identify the majority of HCV seropositive individuals with active infection, which will obviate the need for expensive viral load quantification tests when simplifying HCV diagnosis for the test-to-treat program at the point-of-care.

MO169: Three Doses of SARS‑COV‑2 BNT162B2 MRNA Vaccine Results in an Enhanced Immunologic B- And T-Cell Response in Haemodialysis Patients

BACKGROUND AND AIMSThe immune system is affected by uremia. Haemodialysis (HD) patients have an increased risk of acquiring infections due to many healthcare contacts and have a suboptimal response to vaccination and a high mortality from COVID-19 infection. Accumulating data indicate that two doses of vaccines are not enough, and most HD-patients have now received a third dose. The aim of the study was to describe the antibody and T-cell response to three doses of SARS‑CoV‑2 BNT162b2 mRNA vaccination and change over time.METHODInitially, 50 patients (mean age 69.4 years and 62% men) with end-stage kidney disease (ESKD) and haemodialysis treatment, at the dialysis outpatient clinic, Uppsala Academic Hospital, Sweden were enrolled into the study. Administration of SARS‑CoV‑2 BNT162b2 mRNA vaccine began on 28 Decemeber 2020. In September 2021, the patients received their third vaccine dose. During the study four patients died, four received a kidney transplant and two did not receive the third vaccine dose. A total of 41 (82%) patients received three doses of vaccine and were followed up until 3 months after the third dose. The antibody response was measured at four timepoints; 7–15 weeks and 6–8 months after the second dose, 3 weeks and 3 months after the third dose, and the T-cell response at three timepoints; 7–15 weeks after the second dose, 3 weeks and 3 months after the third dose. SARS-CoV-2 IgG antibody test (Abbott Architect) was performed against Spike antigen (anti-S) positive both after COVID-19 infection and vaccination (quantitative method used in routine diagnostics at Laboratory of Clinical Microbiology, Uppsala) and T-cell reactivity testing against the Spike protein using ELISPOT technology measuring interferon-gamma activity was performed at ABC-labs, Solna.RESULTSAfter two doses, IgG antibodies (IgG abs) to anti-S were detected in 37 (74%) of 50 patients, 5 (10%) had a borderline response and 8 (16%) were negative. T-cell response were detected in 29 (58%) of 50 patients and in 21 (42%) no response was detected. Before the third dose IgG abs to anti-S were detected in 24 (52%) of 46 patients, 3 (7%) had a borderline response and 19 (41%) were negative. Three weeks after the third dose IgG abs to anti-S were detected in 39 (95%) of 41 patients, and 2 (5%) were negative. T-cell responses were detected in 35 (85%) of 41 patients and in 6 (15%) no response. Three months after the third dose IgG ab to anti-S were still detected in 38 (95%) of 40 patients, and 2 (5%) were negative. Changes in IgG ab to anti-S and T-cell response over time in patients who received all three doses of vaccine and were followed up until 3 months after the latest dose (n = 40 and 37) are displayed in Figures 1 and 2 (preliminary data).CONCLUSIONThese results highlight the need for at least three doses of the SARS‑CoV‑2 BNT162b2 mRNA vaccine. It also indicates that the effect of the vaccine decreases slower after dose 3 than after dose 2 since almost all patients had a measurable immune response 3 months after dose 3. However, not all patients develop an immunological response. In a clinical setting, it is justified to measure the antibody response after vaccination to identify patients that are not protected and where one needs to take other measures to protect them from infection and/or to give early treatment in case of symptoms.FIGURE 1:Changes in IgG antibodies to anti-S in patients who received three doses of SARS-CoV-2 BNT162b2 mRNA vaccine and were followed up until 3 months after the latest dose (n = 40).FIGURE 2:Changes T-cell response patients who received three doses of SARS-CoV-2 BNT162b2 mRNA vaccine and were followed up until 3 months after the latest dose (n = 37).

M307 A comparison study between MAGLUMI and Abbott ARCHITECT intact parathyroid hormone (PTH) assay

M307 A comparison study between MAGLUMI and Abbott ARCHITECT intact parathyroid hormone (PTH) assay

Seroprevalence of viral Hepatitis B in the Marrakech region

Viral hepatitis B (HBV) is a major public health problem worldwide. Indeed, the World Health Organization (WHO) estimates that more than 2 billion the number of people who have been exposed to this virus, about 30% of the world population, 18% in sub-Saharan Africa and 41% in Asia, of which 5% with chronic infection or 300-350 million. So the HBV prevalence is 5.4% globally, against 1% for the HIV and 3% for hepatitis C. More than 1 million of them die each year complications essentially cirrhosis and hepatocellular carcinoma. The diagnostic of HBV (recent or chronic infection) relies on research HBs antigen in the serum of patients, it is the witness of a recent or past infection with HBV according to the presence or absence of other serological markers (HBe Ag, anti-HBs Ig and total anti-HBc and anti-HBe antibody IgM) but they do not provide information on the status of viral replication. The detection and quantification of HBV genome (replication of viral marker) can be performed in serum, liver tissue or in blood mononuclear cells. They typically based amplification methods: Polymerase Chain Reaction (PCR). The treatment of viral hepatitis B is for patients with hepatitis B associated with viral replication (HBV DNA positive), cytolysis (elevated transaminases) and presence on biopsy of an activity necroinflammatory or significant fibrosis. Despite the recent antiviral therapeutics, treatment of chronic hepatitis B is difficult and expensive, and the prevention of HBV infection through routine immunization policy and prevention measures currently remains the best option for reducing morbidity and mortality from liver failure and liver cancer. Morocco is considered far, according to WHO data, such as having an intermediate prevalence of viral hepatitis B. Currently, few studies relate the epidemiology of hepatitis B (HBV) in Morocco. The objective of this study was the evaluation of the HBV infection prevalence in a Moroccan workers population, and compare with national and international studies. A total of 20192 individuals were screened for HBsAg. HBV screening was conducted by immunoassay chemiluminescent micro particle (CMIA) PLC (Abbott Architect) and with a prevalence rate of HBsAg estimated at 0.55%. These data are of interest for the diagnosis and prognosis, and therapeutic decision, and can be for the development of an eventual national strategy for the prevention of the transmission of HBV.

Diagnostic accuracy of Abbott Architect Assay as a screening tool for human T-cell leukaemia virus type-1 and type-2 infection in a London teaching hospital with a large solid organ transplant centre.

AimIn the United Kingdom, organ donors/recipients are screened for evidence of human T‐cell leukaemia virus type‐1 and type‐2 (HTLV‐1/2) infections. Since the United Kingdom is a low prevalence country for HTLV infections, a screening assay with high sensitivity and specificity is required. Samples with repeat reactivity on antibody testing are sent to a reference lab for confirmatory serological and molecular testing. In the case of donor screen, this leads to delays in the release of organs and can result in wastage. We aim to assess whether a signal/cut‐off (S/CO) ratio higher than the manufacturer's recommendation of 1.0 in the Abbott Architect antibody assay is a reliable measure of HTLV‐1/2 infection.MethodsWe conducted a 5 year retrospective analysis of 7245 patients from which 11 766 samples were tested on the Abbott Architect rHTLV I/II assay. Reactive samples (S/CO >1) were referred for confirmatory serological and molecular detection (Western Blot and proviral DNA) at UK Health Security Agency, (formerly PHE, Colindale), the national reference laboratory. Electronic, protected laboratory and hospital patient databases were employed to collate data.ResultsA total of 45 patients had initially reactive samples. 42.2% (n = 19/45) had an S/CO ratio > 20, with HTLV infection confirmed in n = 18/19 and indeterminate confirmatory results in n = 1/19. No samples with an S/CO ratio <4 (48.9%, n = 22/45) or 4–20 (8.9%, n = 4/45) had positive confirmatory results on subsequent confirmatory testing.ConclusionSamples with an S/CO >20 likely represent a true HTLV‐1/2 infection. Reactive samples with an S/CO <4 were unlikely to confirm for HTLV infections. Interpretation of these ratios can assist clinicians in the assessment of low reactive samples and reiterates the need for faster access to confirmatory testing.

New Diagnostic Cutoffs for Adrenal Insufficiency After Cosyntropin Stimulation Using Abbott Architect Cortisol Immunoassay

IntroductionThe accurate interpretation of the cosyntropin (adrenocorticotropic hormone [ACTH]) stimulation test requires method- and assay-specific cutoffs of the level of cortisol. Compared with a historical cutoff (18 μg/dL) for polyclonal antibody-based immunoassays, lower thresholds were proposed for the Roche Elecsys II assay, which uses a monoclonal antibody. However, cutoffs for other commonly adopted, monoclonal antibody-based cortisol assays were not yet available. Here, we established the thresholds for the level of cortisol specific to the Abbott Architect immunoassay by comparing the measurements of the level of cortisol using 3 immunoassays. MethodsThe ACTH stimulation test was performed in patients with suspected adrenal insufficiency (n = 50). The serum cortisol level was measured using the Abbott Architect, Roche Elecsys II, and Siemens Centaur assays. The results of the Abbott assay were also compared with those of liquid chromatography-tandem mass spectrometry. The receiver operating characteristic analysis was performed to derive new diagnostic thresholds for the Abbott assay using the polyclonal antibody-based Siemens assay as the reference method. ResultsThe concentrations of cortisol measured using the Abbott assay were similar to those measured using liquid chromatography-tandem mass spectrometry and the Roche Elecsys II assay but significantly lower than those measured using the Siemens assay. The optimized threshold for cortisol using the Abbott assay was 14.6 μg/dL at 60 minutes after stimulation (sensitivity, 92%; specificity, 96%) and 13.2 μg/dL at 30 minutes after stimulation (sensitivity, 100%; specificity, 89%). ConclusionWe recommend a threshold of 14.6 μg/dL for the level of cortisol at 60 minutes after ACTH stimulation for the Abbott assay. In comparison with the historical threshold of 18 μg/dL, the application of the new cutoff may significantly decrease false-positive results due to ACTH stimulation testing. The use of assay-specific cutoffs will be essential for reducing misclassification and overtreatment in patients with suspected adrenal insufficiency.

The utility of HCV core antigen for evaluation of viremia at 48 weeks posttreatment with direct‐acting antivirals

AbstractThe hepatitis C virus core antigen (HCV‐cAg) assay is a cheap and rapid alternative to HCV‐RNA detection, while the results were limited to 12 weeks following direct‐acting antiviral (DAA) treatment. In this study we aimed to investigate the role of the HCV‐cAg assay up to 48 weeks after DAA treatment. We enrolled 98 patients with chronic HCV infection who received DAA treatment in this study. Plasma samples were assessed for HCV‐RNA (AmpliPrep/COBAS TaqMan assay, Roche) and HCV‐cAg (Abbott ARCHITECT HCV‐cAg assay) levels at baseline, 12 weeks (P12) and 48 weeks (P48) after DAA treatment. The sensitivity and specificity of HCV‐cAg were compared with those of HCV‐RNA. A total of 284 samples from 98 enrolled participants were analyzed. HCV‐cAg levels changed in parallel with HCV‐RNA levels in HCV‐infected patients during and after DAA therapy. HCV‐cAg levels showed excellent correlation with HCV viral load (R = 0.951, R2 = 0.905, β = 0.951, and P &lt; .001). The overall sensitivity and specificity for HCV‐cAg in detecting quantifiable HCV‐RNA thresholds were 96.9% and 100%, respectively. Three patients with baseline HCV viremia had nonreactive HCV‐cAg (false‐negative rate was 1.02%); none of the patients were HCV‐cAg positive and HCV‐RNA negative. At 48 weeks after DAA treatment, the HCV‐cAg assay detected all patients with viremia, demonstrating 100% sensitivity and specificity. In conclusions, the HCV‐cAg assay has high sensitivity and specificity for the detection of pre‐ and post‐DAA treatment viremia and may be a useful tool to confirm viremia at P12 and P48.

Evaluation of a personalized, dose-sparing revaccination strategy in hepatitis B vaccine non-responders

ObjectivesThe detection of low levels of antibodies against HBsAg (anti-HBs) below 10 IU/L in non-responders after a primary hepatitis B vaccination, is associated with seroconversion after revaccination. We compared the diagnostic performance of four anti-HBs assays in non-responders in their ability to differentiate between absence or presence of low levels of anti-HBs and propose a revaccination strategy guided by anti-HBs titres. MethodsNon-responders were revaccinated with Fendrix 20 μg at 0, 1 and 2 months. Anti-HBs titres were determined by Abbott Architect, Diasorin Liaison, Roche Cobas and Siemens ADVIA Centaur. Inter-assay agreement was evaluated with Cohen’s Kappa (k) in baseline samples between zero-responders without detectable antibodies and poor-responders with detectable antibodies < 10 IU/L. Seroconversion rates and geometric mean titres were analysed at 0, 1 and 3 months. A titre-based strategy (one revaccination dose and anti-HBs measurement followed by two more revaccination doses if required) was compared with the standard revaccination series of 3 doses. Results57 participants were included in the analysis. k was ≥ 0.65 for all assays except ADVIA (k ≤ 0.41). After one revaccination dose all assays detected a mean seroconversion rate in zero-responders of 42.9%, compared to 85.1% in poor-responders. The difference between zero- and poor-responders in seroconversion rate per assay was significant (p < 0.05). After three revaccination doses the mean seroconversion rate was 88.2% in zero-responders and 98.5% in poor-responders (p > 0.286 per assay). A titre-based strategy reduced the amount of revaccinations by 17% compared with the standard. ConclusionsAll assays demonstrated a comparable difference in seroconversion rate between zero- and poor-responders after one revaccination dose. The revaccination strategy could be optimised by differentiation between zero- and poor-responders followed by a titre-guided schedule.

Diagnostic performance of a rapid, novel, whole blood, point of care high-sensitivity cardiac troponin I assay for myocardial infarction

BackgroundWe evaluated the diagnostic performance of a whole blood, point of care (POC) high-sensitivity cardiac troponin I (hs-cTnI) assay for myocardial infarction (MI) compared to central laboratory assays. MethodsConsecutive patients presenting to the emergency department with symptoms of ischemia were studied. Serial hs-cTnI testing was based on clinical indication at presentation. Parallel measurements were made using fresh whole blood on Siemens Atellica VTLi POC assay, EDTA plasma on Abbott ARCHITECT i2000 used in practice, and heparin plasma on Siemens Atellica. MI was determined according to the Fourth Universal Definition of MI using 99th percentiles. Sensitivities and negative predictive values (NPV) were calculated using 99th percentile URLs. Results1089 Patients, 418 females and 671 males, were enrolled. There were 91 (8.4%) MIs. At baseline (0 h), POC hs-cTnI assay had a sensitivity of 65.7% (95% CI 47.8–80.9) for females and 67.9% (54.0–79.7) for males and NPV of 96.4% (93.9–98.1) for females and 96.7% (94.9–98.0) for males. At 2 h, sensitivity improved to 82.9% (66.4–93.4) for females and 80.4% (67.6–89.8) for males, while NPV improved to 98.2% (96.1–99.3) and 97.9% (96.3–99.0), respectively. For central laboratory assays, comparable diagnostics were observed at 2 h: females - sensitivity 94.3% (80.8–99.3) for ARCHITECT and 79.4% (62.1–91.3) for Atellica, and NPV 99.3% (97.6–99.9) and 98.0% (95.8–99.2), respectively; males - sensitivity 87.5% (75.9–94.8) for ARCHITECT and 80.4% (67.6–89.8) for Atellica, NPVs of 98.7% (97.3–99.5) and 97.9% (96.3–99.0), respectively. ConclusionsThe POC, whole blood Atellica VTLi hs-cTnI assay demonstrated comparable diagnostic accuracy for MI to central laboratory assays using 99th percentiles.

Higher Antibody Concentrations in U.S. Health Care Workers Associated with Greater Reactogenicity Post-Vaccination.

Multiple factors may be associated with immune responses to SARS-CoV-2 vaccines. Factors potentially related to magnitude and durability of response include age, time, and vaccine reactogenicity. This study analyzed SARS-CoV-2 IgG spike antibody responses following the second dose of vaccine in healthcare workers (HCWs). Data were collected from participants enrolled in a longitudinal SARS-CoV-2 serology study over a 12-month period. Participants completed a survey documenting symptoms post-vaccination. Serum specimens were tested for SARS-CoV-2 IgG antibodies using the Abbott Architect AdvisdeDx SARS-CoV-2 IgGII assay. Antibody levels were compared against time from second vaccine dose, and symptoms following vaccination. Altogether, 335 women (86.6%) and 52 men (13.4%) participated. Median age was 37 years (IQR 30-43). Overall median antibody level was 2150.80 [1246.12, 3556.98] AU/mL (IQR). Age was not associated with antibody concentration (p-value = 0.10). Higher antibody responses (2253 AU/mL vs. 1506 AU/mL; p = 0.008) were found in HCWs with one or more symptoms after the second dose of the vaccine (n = 311). Antibody responses persisted throughout the study period post-vaccination; statistically significant decreases in antibody responses were observed over time (p < 0.001). Higher antibody response was associated with reactogenicity post-vaccine. Age and sex were not associated with higher antibody responses.

Comparison of a novel automated DiaSys procalcitonin immunoassay with four different BRAHMS-partnered immunoassays

ObjectivesProcalcitonin (PCT) is an important biomarker of sepsis and respiratory infections. Various automated immunoassays for measuring PCT in patient plasma are available in medical laboratories. However, due to a lack of international reference material for PCT, the assays are not always comparable. Design and methodsIn this study, we compared a new turbidimetric immunoassay from DiaSys, measured on the Abbott Architect c16000 and Alinity c, with four BRAHMS-associated chemiluminescence immunoassays (Abbott Architect i2000SR, Alinity i, Roche Cobas e411 and DiaSorin Liaison XL) using 120 random patient plasma samples from the clinical laboratory routine at the University Medical Center Goettingen. ResultsThe DiaSys assay showed clear differences as compared to the BRAHMS-associated assays when measured on Architect c: i.e. 58% positive mean bias vs. Architect i, 67% vs. Cobas and 23% vs. Liaison. As a result, additional 19% our patients would have a suspected bacterial infection, when using PCT values from the DiaSys assay and commonly accepted decision limits. A crosscheck of the DiaSys calibrator on the BRAHMS-associated systems showed a low recovery of the calibrator material (approx. 50%). ConclusionsOverall, this study shows significant differences between the DiaSys and BRAHMS-associated assays. This could be attributed to a potential DiaSys calibrator problem. This highlights the need for an international reference material for harmonization of the PCT assays.

The Relation between the Plasma Level of Testosterone Hormone and the Severity of COVID-19 in Iraqi Patients

Coronavirus disease 2019 discovered in December 2019, Wuhan, China. It was transmitted globally producing the present COVID-19 pandemic. Concerns have been raised about the potential impact of COVID-19 on male reproductive organs and male fertility as the number of infections in the male community has increased. The objectives of current study are studying the relationship between the plasma levels of testosterone and the markers of immune reaction with the severity and mortality in a sample of COVID-19 patients. A cross section study included NO= 103 male patients affected by SARS- CoV-2 pneumonia, diagnosed by PCR and chest CT scan, (≥ 18 years old), and recovered in the respiratory intensive care unit (RICU). Several biochemical risk factors were determined Free Testosterone, sex hormone binding globulin (SHBG) were measured by Enzyme-Linked Immunosorbent Assay(ELISA), D-dimer, Ferritin, CRP, Urea, Creatinine were measured by automated method by using Abbott Architect c4000 and Complete Blood Count(CBC). The results show that the serum free testosterone and SHBG levels a significant lower in non-survivor patients than survivor patients with COVID-19. While the other biomarkers (D-dimer, Ferritin, Urea, Creatinine) were significant higher in non-survivor patients than survivor patients. The CRP, WBC and lymphocyte showed that no significant between the both group of patients. In conclusion the study showed that lower free testosterone and SHBG levels enable significant role in increasing risk of COVID-19 mortality amongst adult male patients

Automation in Busulfan Therapeutic Drug Monitoring: Evaluation of an Immunoassay on two Routine Chemistry Analyzers.

Therapeutic drug monitoring (TDM) of busulfan is recommended for hematopoietic stem cell transplant recipients. Timely reporting of these TDM results is essential given the short administration period and the planned dose adjustments on day 2. The authors evaluated the performance of a new nanoparticle-based competitive immunoassay on two routine clinical chemistry analyzers and compared its performance to that of an in-house high-resolution mass spectrometry (HRMS) method. The MyCare Oncology Busulfan Assay Kit (Saladax Biomedical) was applied on two routine clinical chemistry analyzers (Abbott Architect c8000 and Roche Cobas c502) with a linearity range of 187-2000 ng/mL. The study evaluation measured imprecision and accuracy, sample probe carry-over, and dilution integrity. Method comparison with liquid chromatography (LC)-HRMS was performed using samples from patients undergoing busulfan treatment. Within- and between-run coefficient of variations for both analyzers were ≤5.23% and ≤8.45%, respectively, across the busulfan concentration range. The obtained biases were ≤10.3%. Both analyzers met the acceptance criteria for sample probe carry-over and dilution integrity. Agreement between the immunoassay and LC-HRMS was high: 92% and 89% of the samples measured on Architect and Cobas, respectively, were within the ±15% limit compared to the corresponding LC-HRMS results. Overall, good analytical performance and high agreement with LC-HRMS results were obtained for the immunoassay installed on both routine clinical chemistry analyzers. Therefore, this assay could be implemented as a valid alternative for LC methods in clinical laboratories on different open-channel clinical chemistry analyzers, resulting in shorter turn-around times for reporting busulfan TDM results with subsequent faster dosage adjustments.

IDF21-0084 Role of serum copeptin levels in Type II Diabetes Mellitus patients with progressive stages of diabetic nephropathy

Background: Type II Diabetes mellitus (DM) is one of the leading metabolic diseases. It has multiple serious complications. Diabetic nephropathy is one of them. Progressive deterioration in renal functions due to DM makes the patient’s life completely handicapped. Thus, patients start depending on dialysis and ultimately develop its complications. Arginine Vasopressin (AVP) maintains glucose hemostasis and therefore, plays an important role in the pathophysiology of DM and its related complications such as diabetic nephropathy. Copeptin is an inactive analogue of AVP and considered as a reliable surrogate biomarker of AVP. Therefore, it is hypothesized that changes in the levels of copeptin can be correlated with diabetic and renal markers and thus may have potential role in predicting progressive stages of DM and diabetic nephropathy. Aim: The aim of the study is to find out the relation of copeptin with different diabetic and renal function biomarkers and to find out a potential role of copeptin as a predictive biomarker in DM and its associated progressive diabetic nephropathy. Method: It was a comparative cross-sectional study. A total number of 120 individuals were recruited into four groups i.e. controls, pre- diabetes, DM without nephropathy and DM with nephropathy as per the criteria of American Diabetes Association (ADA) 2018 and National Kidney Foundation/ Kidney Disease Outcome Quality Initiative (NKF/ KDOQI) 2018 guidelines. All cases were controlled hypertensive. Serum copeptin levels were measured by sandwich ELISA. While, Blood Urea Nitrogen (BUN), creatinine, Glycosylated Hemoglobin (HbA1c), urine micro albumin (UAE) and urinary creatinine were got done using spectrophotometry on Abbott Architect c8000 and electrolytes (Na+, K+ and Cl−) by iso electric method from Dow Diagnostic Research and Reference Laboratory (DDRRL), Dow University of Health Sciences. Statistical analysis was done using Analysis of Variance (ANOVA) and Pearson’s correlation tests on SPSS. Confounders were controlled using univariate linear regression. Results: The average copeptin levels of the study population were 215.096 pg/ml. Copeptin levels were significantly elevated in subjects with positive family history of DM (p = 0.025), levels were also raised in pre diabetes patients (252.85pg/ml) as compared to other groups. Copeptin levels were positively correlated with HbA1c r=0.171 (p=0.101), urea r=0.244 (p=0.007), creatinine r=0.215 (p=0.018), UAE r=0.310 (p=0.001), UACR r=0.375 (p=< 0.001). No significant correlation of copeptin was found with major electrolytes of the body. However, copeptin is found to be significantly associated with progressive stages of albuminuria and declining Glomerular Filtration Rate (GFR). Discussion: The raised levels of copeptin in subjects with positive family history of DM recommends its role in the early prediction of DM. Moreover, significant association of copeptin with progressive stages of albuminuria and declining GFR suggest the contribution of copeptin in the worsening of renal functions in DM and its associated nephropathy.

A cohort study measuring SARS-CoV-2 seroconversion and serial viral testing in university students

BackgroundTo improve understanding of the antibody response to SARS-CoV-2 infection, we examined seroprevalence, incidence of infection, and seroconversion among a cohort of young adults living on university campuses during the fall of 2020.MethodsAt the beginning (semester start) and end (semester end) of an 11-week period, serum collected from 107 students was tested using the qualitative Abbott Architect SARS-CoV-2 IgG and AdviseDx SARS-CoV-2 IgG II assays. Results were matched to interim weekly surveillance viral testing and symptom data.ResultsWith the SARS-CoV-2 IgG assay, 15 (14.0%) students were seropositive at semester start; 29 (27.1%) students were seropositive at semester end; 10 (9.3%) were seropositive at both times. With the AdviseDx SARS-CoV-2 IgG II assay, 17 (16.3%) students were seropositive at semester start, 37 (35.6%) were seropositive at semester end, and 16 (15.3%) were seropositive at both times. Overall, 23 students (21.5%) had positive viral tests during the semester. Infection was identified by serial testing in a large majority of individuals who seroconverted using both assays. Those seropositive at semester end more frequently reported symptomatic infections (56.5%) than asymptomatic infections (30.4%).ConclusionDifferences between antibody targets were observed, with more declines in antibody index values below the threshold of positivity with the anti-nucleocapsid assay compared to the anti-spike assay. Serology testing, combined with serial viral testing, can detect seroconversions, and help understand the potential correlates of protection provided by antibodies to SARS-CoV-2.

True-positive reflex threshold value for HCV antibody screening test.

The use of a signal-to-cut-off ratio has been recommended by the Centre for Disease Control and Prevention to determine the need for further validation using a supplemental test. In this study, we aimed to determine the optimal true-positive signal-to-cut-off ratio for the ABBOTT ARCHITECT i2000SR immunoassay (Abbott Laboratories, Illinois, USA), using the Serodia® HCV particle agglutination (HCV-PA) assay (Fujirebio Inc, Tokyo, Japan) as the reference test for anti-HCV screening. We analysed a total of 13,240 specimens using the ARCHITECT i2000SR immunoassay and subsequently subjected all the reactive specimens with a signal-to-cut-off ratio ≥ 1.00 (n = 267) to the Serodia® HCV-PA reference assay. Receiver operating characteristic (ROC) curve analysis was carried out and performance characteristics for each signal-to-cut-off ratio were determined. The selected signal-to-cut-off ratio value was then assessed using a line immunoassay (LIA) test. ROC curve analysis determined that the optimal signal-to-cut-off ratio was 5.05, which gave the highest Youden's Index (J) value of 0.89, with a sensitivity of 93.1% (88.9-97.2), a specificity of 96.0% (92.4-99.4), a positive predictive value of 96.4% (93.3-99.5), and a negative predictive value of 92.2% (87.5-96.8). Validation of the optimal S/Co value using the LIA test yielded an accuracy of 91.8%, with sensitivity and specificity values of 92.0% and 91.7%, respectively. The optimal signal-to-cut-off ratio value for the ARCHITECT i2000SR immunoassay, which was determined using HCV-PA assay as the reference test and validated using a HCV-LIA assay, showed high sensitivity and specificity, and may be used in routine anti-HCV screening.

Anti-SARS-CoV-2 Antibody Responses 5 Months Post Complete Vaccination of Moroccan Healthcare Workers.

Data about the duration of antibodies after vaccination show that the protection against SARS-CoV-2 infection begins to decline over time. This study aims to determine anti-SARS-CoV-2 anti-S IgG levels in healthcare workers five months after the second vaccination dose. We collected samples from 82 participants who were fully vaccinated with ChAdOx1 nCoV-19 or BBIBP-CorV. We assessed anti-SARS-CoV-2 IgG antibodies using a Euroimmun ELISA and an Abbott Architect ™ SARS-CoV-2 IgG test. Of the 82 participants, 65.85% were seropositive for IgG using ELISA, and 86.59% were positive for IgG according to the Abbott Architect ™ test. Individuals vaccinated with the ChAdOx1 nCoV-19 vaccine had a median anti-S1 antibody level of 1.810 AU/mL [interquartile range (IQR), 1.080–3.7340] and 171.7 AU/mL [79.9–684.6] according to the Euroimmun ELISA and Abbott Architect test, respectively. These tests indicated that people vaccinated with BBIBP-CorV had a median anti-S1 antibody level of 1.840 AU/mL [0.810–2.960] and 126.7 AU/mL [54.9–474.3], respectively. Statistical analysis showed no significant difference between the positivity rates of the vaccinated individuals, either for gender or for age. In addition, we found no significant difference between the two vaccines. Our study provides information on the longevity of the anti-SARS-CoV-2 IgG antibodies in people at least five months after vaccination.

Retrospective Analysis of Hepatitis B and Hepatitis C Viruses and HIV Infections in Patients Presenting to the General Surgery Clinic and Evaluated Preoperatively

Aim: Hepatitis B(HBV), Hepatitis C(HCV) and HIV infections are important parenterally transmitted infections. The aim of this study is to determine the seroprevalence of HBsAg, anti-HBs, anti-HCV and anti-HIV in patients with preoperative preparation.&#x0D; Materials and MethodS: Anti-HBs, HBsAg, anti-HCV, anti-HIV tests with chemiluminescent enzyme immune-assay method in a total of 900 patients applied to the General Surgery Clinic and were evaluated preoperatively by Abbott Architect i1000 immunoassay analyzer (Abbott Diagnostics, Illinois, USA) operated according to the manufacturer's instructions. Anti-HBs titer above 10 IU/mL, serum optical density/”cut-off” control optical density (S/Co) ≥1 in HBsAg, anti HCV and anti-HIV tests were accepted as positive. HBV-DNA and HCV RNA tests were performed with real-time PCR method.&#x0D; Results: Anti-HBs test was found to be reactive in 34.11% and nonreactive in 65.89%. HBsAg positivity was 1.0% (9/900), and anti-HCV positivity was 0.33% (3/900). Anti-HIV positivity and HBsAg-anti-HCV association were not detected. Six patients with HBsAg positivity and one patient with anti-HCV positivity were found incidentally during preoperative examinations.&#x0D; Conclusion:As a result of these data, it can be concluded that cost-effective serological tests for HBV and HCV infections performed in the preoperative period are extremely important in the detection of asymptomatic patients. Preoperative screening is important in terms of early diagnosis of patients before complications such as cirrhosis and HCC develop, enabling treatment, as well as enabling healthcare professionals to increase infection control measures while intervening with infected patients, to be more careful in terms of percutaneous injuries, and to reduce the risk of transmission.

Evaluation of hepatitis C virus antibody assay using dried blood spot samples

Early diagnosis of hepatitis C virus (HCV) infection is essential for prompt initiation of treatment and prevention of transmission, yet several logistical barriers continue to limit access to HCV testing. Dried blood spot (DBS) technology involves a simple fingerstick that eliminates the need for trained personnel, and DBS can be stored and transported at room temperature. We evaluated the use of DBS whole blood samples in the modified Abbott ARCHITECT anti-HCV assay, comparing assay performance against the standard assay run using DBS and venous plasma samples. 144 HCV positive and 104 HCV negative matched venous plasma and whole blood specimens were selected from a retrospective study with convenience sampling in Cameroon. Results obtained using a modified volume DBS assay were highly correlated to the results of the standard assay run with plasma on clinical samples and dilution series (R2 = 0.71 and 0.99 respectively). The ARCHITECT Anti-HCV assay with input volume modification more accurately detects HCV antibodies in DBS whole blood samples with 100% sensitivity and specificity, while the standard assay had 90.97% sensitivity. The use of DBS has the potential to expand access to HCV testing to underserved or marginalized populations with limited access to direct HCV care.