Routine Chemistry Research Articles

Strategies to shorten turnaround time in outpatient laboratory.

BackgroundTurnaround time (TAT) is one of the most important indicators of laboratory quality. For the outpatient routine chemistry tests whose results are checked by clinicians on the same day, we set a quality goal that >90% of these samples should be reported within 60 min. As more than 20% of the samples failed to achieve this goal in 2020, we introduced an additional autoanalyzer and a real‐time monitoring system to improve this rate.MethodsAs the TAT of the pre‐analytical phase is the greatest contributor to TAT, we divided it into sampling, sample transport, and sample preparation times. An additional autoanalyzer was introduced, and its effect on TAT improvement was evaluated with the TAT data of June and July 2020. A real‐time monitoring system was introduced to sort delayed samples, and its effect was assessed with the TAT data of June and July 2021. TAT data from December 2019 to January 2020 were set as baseline controls.ResultsThe preparation time comprised the largest proportion of TAT. Although there was a slight decrease in overall TAT after the introduction of the above two strategies, the target TAT achievement rate increased significantly from 78.5% to 88.7% (p < 0.001).ConclusionsWe checked the cause of TAT prolongation and introduced new strategies to improve it. The addition of an autoanalyzer per se was not so effective but was better when combined with the real‐time monitoring system. Such strategies would increase the quality of the laboratory services.

Evaluation of serum and rapid serum separator collection tubes for therapeutic drug assays

Appropriate specimen collection and storage is essential to preserve sample integrity and ensure accurate test results. The default collection containers for blood drug concentrations are tubes without gel separators to avoid possible drug adsorption. However, routine chemistry tests are generally collected in gel separator tubes due to their convenient transport and processing; collection of an additional gel-free tube is often required for drug measurements.Citrated whole blood was pooled, spiked with drug, and transferred to three tubes (red, SST gold, RST orange) containing calcium chloride. Blood was allowed to clot, centrifuged and stored at ambient temperature (24 h) or refrigerated (7 days). At defined times, serum drug concentrations were determined (Roche cobas c502). Based on these results, specimen collection requirements were updated to allow serum separator tubes for 17 assays.Of the 21 assays evaluated, 18 displayed acceptable stability in both gel-containing tubes (acetaminophen, amikacin, carbamazepine, digoxin, ethanol, gentamicin, lamotrigine, levetiracetam, lithium, methotrexate, phenobarbital, phenytoin, salicylate, theophylline, tobramycin, valproic acid, vancomycin, voriconazole). Three drugs displayed strong decreases in measured concentrations after storage in one or both gel-containing tubes (total tricyclics, lidocaine, and free phenytoin). Following adoption of gel-containing tubes, 94% of the five most frequently ordered drug monitoring tests in the Emergency Department were collected in serum separator tubes.Evaluation of the stability and accuracy of commonly monitored drugs revealed that the majority were not affected by exposure to gel separator material under conditions similar to outpatient clinic storage, courier transport, and laboratory storage. Expanding the collection requirements for appropriate drugs to include gel separator tubes decreases the number of specimens drawn and the complexity of laboratory workflows.

Retrospective analysis of the relationship between bone mineral density and body composition in a health check-up Chinese population.

PurposeThis study was designed to explore the relationship between bone mineral density (BMD) and body composition indicators in Chinese adults (≥50 years) in order to provide a scientific basis for optimal bone health management.MethodIndividuals ≥50 years old who received physical examinations and routine check-ups at the Health Management Research Institute of PLA General Hospital from September 2014 through March 2022 were included as research subjects in this study. Basic clinical and demographic information were recorded for all subjects, along with smoking and drinking status, height and body weight. A panel of routine blood chemistry and metabolite markers were measured, along with lean muscle mass and body fat mass using body composition bioelectrical impedance analysis (BIA). Body mass index (BMI), body fat percentage (BFP), skeletal muscle mass index (SMI), and bone mineral density (BMD) were calculated for all individuals. For comparative analysis, individuals were grouped based on their BMI, BFP, SMI and BMD T-score. Follow-up examinations were performed in a cohort of 1,608 individuals matched for age, sex, smoking and drinking history for ≥5 years,ResultsIn this large cross-sectional study, age, smoking, homocysteine (Hcy) and blood glucose levels were established as independent risk factors for osteoporosis. Multi-factor logistic regression analysis showed that age, sex, BMI, intact parathyroid hormone (iPTH), SMI, BFP, smoking, blood levels of inorganic phosphate (P) and K+ were all significantly associated with osteoporosis risk (P<0.05). A subset of these factors- BMI, SMI, BFP and K+, were determined to be protective. In the cohort followed for ≥5 years, SMI and BMD decreased while BFP and BMI increased significantly (P<0.001) over time.ConclusionRisk of osteoporosis may be reduced by increasing body weight, particularly lean muscle mass, while simultaneously controlling BFP.

210-OR: Presence of Type 2 Diabetes (T2D) Affects HDL Particle Proteomic Composition Independently of Obesity or Fatty Liver

Patients with T2D remain at high risk of cardiovascular (CV) events despite adequate glycemic and LDL-C control. Changes in HDL particle composition and function may explain part of this increased CV risk. The aim of this study was to determine the proteomic composition of isolated HDL particles in T2D patients, and establish which factors contribute to these abnormalities. Patients (n=213) with and without T2D were included in the study and underwent an OGTT, liver MRS, and routine blood chemistries. Advanced lipid testing and lipoprotein subfractions were measured by ion mobility. ApoA-I containing particles (i.e., HDL) were isolated and a novel targeted proteomic approach using multiple reaction monitoring (MRM) by liquid chromatography and tandem mass spectrometry (LC-MS/MS) was undertaken to measure HDL-bound proteins. Patients with (n=146) vs. without (n=67) T2D were older (56±9 vs. 47±12) , more obese (34.2±4.7 vs. 32.6±5.3 kg/m2) , but had no significant differences in other important clinical characteristics, such as gender or race. Patients with T2D had lower HDL-C (38±9 vs. 43±13 mg/dl, p&amp;lt;0.001) , but no difference in the number of HDL particles. A panel of 28 HDL-bound proteins were targeted and quantified by MRM LC-MS/MS. After correction for multiple comparisons (false discovery rate set at 5%) and adjustment for obesity and NAFLD, 4 proteins were found to be decreased in T2D patients (ApoA-I, ApoC-I, ApoM, and PON3; all p&amp;lt;0.0015) . The pCAD index (well-validated score for coronary artery disease and CV mortality based on HDL-bound proteins) was increased in patients with T2D, irrespectively of obesity or NAFLD (93±15 vs. 61±38, p&amp;lt;0.0001) . In conclusion, patients with T2D showed significant differences in the apolipoproteomic composition of HDL particles, and this translated into increased CV risk based on pCAD index. Different HDL composition and function may explain the residual CV risk of patients with T2D optimally treated for hyperglycemia and LDL-C. Disclosure F.Bril: None. R.Pearce: Employee; Quest Diagnostics. T.S.Collier: Employee; Quest Diagnostics, Stock/Shareholder; Quest Diagnostics. S.Kalavalapalli: None. M.J.Mcphaul: Employee; Quest Diagnostics. K.Cusi: Consultant; Altimmune, Arrowhead Pharmaceuticals, Inc., AstraZeneca, Boehringer Ingelheim International GmbH, Bristol-Myers Squibb Company, Eli Lilly and Company, Fractyl Health, Inc., Genentech, Inc., Hanmi Pharm. Co., Ltd., Intercept Pharmaceuticals, Inc., Novo Nordisk. Funding American Diabetes Association (1-08-CR-08) ; The Obesity Society (Early-Career Research Grant) Veterans Affairs (1 I01 CX000167-01) . UF CTSI (UL1TR001427)

Comparison of blood collection tubes for 29 biochemical analytes in pediatric patients with central venous catheters

BackgroundPediatric cancer patients undergoing chemotherapy or radiation therapy generally require a central venous catheter (CVC). However, serum drawn from CVCs has several drawbacks for use in routine chemistry tests. Biochemical analytes were evaluated using heparin plasma instead of serum to maintain turnaround time and to prevent problems caused by micro-clot formation or delayed clotting time. MethodsVenous blood samples from 52 pediatric oncology patients with chemoports or Hickman catheters were collected in serum separating tubes (SSTs) and lithium heparin tubes (LHTs). A total of 29 parameters were analyzed on a Cobas c702 (Roche Diagnostics, Mannheim, Germany). Passing-Bablok regression and Bland-Altman difference plots were used for statistical analyses. ResultsWhen the mean value of each analyte measured from LHT was compared with those from SST, percentage bias was within the desirable bias limit in most of the analytes. However, albumin, potassium, and inorganic phosphorus showed a negative constant bias of −3.0%, −5.3%, and −1.6%, respectively, and total protein showed a positive constant bias of + 3.8%. ConclusionsThe use of LHTs for sample collection from pediatric patients with CVCs could be helpful for routine chemistry analyses. The results of potassium and total protein should be interpreted with consideration of the difference between serum and plasma samples.

Impact of recentrifugation of blood collection tubes on chemistry and immunochemistry analytes after 24 and 72 hours of refrigerated storage on the Roche Cobas 8000 platform

BackgroundWe discovered that blood collection tubes (BCTs) were inadvertently recentrifuged due to improper placement on our automated preanalytical system. This study was undertaken to determine the impact of recentrifugation of blood specimens collected in serum separator (SSTs) and plasma separator (PSTs) tubes after refrigerated storage for 24 and 72 h on the concentrations of chemistry and immunochemistry analytes. MethodsBlood was collected from 20 volunteers in SSTs and PSTs, centrifuged, and 36 chemistry and 14 immunochemistry analytes were measured at baseline in single-centrifuged tubes on a Roche Cobas 8000 chemistry platform. After baseline testing, the BCTs were refrigerated for 24 or 72 h, recentrifuged and retested. The results were compared to the single-centrifuged tubes for statistical significance. ResultsRecentrifugation of BCTs after 24 or 72 h of refrigerated storage showed statistically significant increases in lactate dehydrogenase activity and potassium concentration and statistically significant decreases in glucose (except in SSTs after 24 h of refrigerated storage) and CO2 concentration, but no significant differences in immunochemistry analyte concentrations. ConclusionIt may be safe to report most routine chemistry and immunochemistry analyte concentrations from recentrifuged SSTs and PSTs on the Roche Cobas 8000, which may save time and costs associated with recollection and retesting.

M094 Evaluation of moving average as continuous analytical quality control for routine chemistry and hematology parameters

M094 Evaluation of moving average as continuous analytical quality control for routine chemistry and hematology parameters

The effect of extracorporeal shock wave therapy in acute traumatic spinal cord injury on motor and sensory function within 6\u2009months post-injury: a study protocol for a two-arm three-stage adaptive, prospective, multi-center, randomized, blinded, placebo-controlled clinical trial

BackgroundThe pathological mechanism in acute spinal cord injury (SCI) is dual sequential: the primary mechanical lesion and the secondary injury due to a cascade of biochemical and pathological changes initiated by the primary lesion. Therapeutic approaches have focused on modulating the mechanisms of secondary injury. Despite extensive efforts in the treatment of SCI, there is yet no causal, curative treatment approach available.Extracorporeal shock wave therapy (ESWT) has been successfully implemented in clinical use. Biological responses to therapeutic shock waves include altered metabolic activity of various cell types due to direct and indirect mechanotransduction leading to improved migration, proliferation, chemotaxis, modulation of the inflammatory response, angiogenesis, and neovascularization, thus inducing rather a regeneration than repair.The aim of this clinical study is to investigate the effect of ESWT in humans within the first 48 h after an acute traumatic SCI, with the objective to intervene in the secondary injury phase in order to reduce the extent of neuronal loss.MethodsThis two-arm three-stage adaptive, prospective, multi-center, randomized, blinded, placebo-controlled study has been initiated in July 2020, and a total of 82 patients with acute traumatic SCI will be recruited for the first stage in 15 participating hospitals as part of a two-armed three-stage adaptive trial design. The focused ESWT (energy flux density: 0.1–0.19 mJ/mm2, frequency: 2–5 Hz) is applied once at the level of the lesion, five segments above/below, and on the plantar surface of both feet within the first 48 h after trauma.The degree of improvement in motor and sensory function after 6 months post-injury is the primary endpoint of the study. Secondary endpoints include routine blood chemistry parameters, the degree of spasticity, the ability to walk, urological function, quality of life, and the independence in everyday life.DiscussionThe application of ESWT activates the nervous tissue regeneration involving a multitude of various biochemical and cellular events and leads to a decreased neuronal loss. ESWT might contribute to an improvement in the treatment of acute traumatic SCI in future clinical use.Trial registrationClinicalTrials.govNCT04474106

The effect of riparian pool‐riffles on the hydrochemistry of hyporheic habitats: The River Esk, Yorkshire, UK

AbstractEuropean Union Water Framework Directive (WFD) (2000/60/EC) waterbody statuses are often derived from the assemblage of mixed‐taxon organisms found within bed sediments. Yet no routine water chemistry samples are taken from riverbed substrate, despite many interstitial species being dependant on specific physicochemical conditions. This paper examines water and nutrient exchanges between stream and substrate, the hyporheic zone, and the consequent alteration to the chemistry of interstitial and in‐stream waters, which in turn leads to small‐scale but significant changes in habitat. Bed topography, principally a pool‐riffle sequence, was surveyed and hydraulically sampled to examine the hyporheic flow pathways generated between the stream, substrate, and groundwater—creating an ecotone. Hyporheic zone, in‐stream and groundwater hydrochemistry, and hydraulic measures were assessed at a braided woodland river reach using a dense monitoring approach. The findings demonstrate that through a 23‐m pool‐riffle sequence, where water infiltrates at the riffle‐head and subsequently exfiltrates at the riffle‐tail, there is a 5% reduction in mean in‐stream nitrate‐N and a 73% reduction in hyporheic zone concentration. When calcium‐enriched riffle‐tail exfiltrate meets riffle‐runoff water that is turbulently oxygenated from riffle‐flow, an interstitial redoxcline is created. Dissolved oxygen nocturnally drops, with photosynthetic rate reduction, which causes hyporheic nitrate‐N to double its daytime concentration. The results are related to the Yorkshire River Esk freshwater pearl mussels, Margaritifera margaritifera Linnaeus (1758), a declining endangered species. At present, scant monitoring of interstitial hydrochemistry and diurnal change across stream and substrate occurs.

Use of Cotton Balls in Diapers for Collection of Urine Samples Impacts the Analysis of Routine Chemistry Tests: An Evaluation of Cotton Balls, Diapers, and Chemistry Analyzers

To evaluate the suitability of urine samples collected with cotton balls placed into diapers for routine laboratory chemistry analyses. Twenty pools of residual unpreserved urine samples were separated into control and treated aliquots. The treated samples were absorbed into 2 different brands of cotton balls, wrapped in 3 different brands of diapers, and incubated at 37°C for 1hour. The urine-soaked cotton balls were placed into a syringe and expressed via plunger depression. Urine sodium, potassium, creatinine, urea, calcium, magnesium, inorganic phosphorus, albumin, and total protein were measured on all samples on 5 automated clinical chemistry platforms: Ortho Vitros 4600, Siemens Dimension Vista 500, Beckman Coulter AU5822, Roche Cobas 6000, and Abbott Architect c8000 at 5 separate hospital laboratories. Criteria used to exclude the presence of significant effects of urine from presoaked cotton balls in a diaper on the measurement of chemistry laboratory tests were R2 >0.95, slope of 0.9-1.1, and mean bias within ±10%. Albumin and total protein measurements demonstrated significant negative bias in urine from both brands of presoaked cotton balls with all brands of diapers on all 5 chemistry platforms compared with the control urine. We did not observe a significant effect of presoaking urine in cotton balls in a diaper on the measurement of sodium, inorganic phosphorus, and urea. The remaining tests demonstrated significant effects when measured in urine from presoaked cotton balls and/or diapers that were specific to the chemistry analyzer platform or diaper. Diaper and cotton ball-based urine collection significantly impacts the measurement of several common chemistry assays.

Continuous monitoring of SARS-CoV-2 seroprevalence in children using residual blood samples from routine clinical chemistry.

The assessment of SARS-CoV-2 infections in children is still challenging, but essential for appropriate political decisions. The aim of this study was to investigate whether residual blood samples can be used for SARS-CoV-2 seroprevalence monitoring in pediatrics. In this repeated cross-sectional cohort study, anonymous residual blood samples from pediatric patients aged 0-17 years were collected in three time-periods (Oct.-Nov. 2020, April 2021, and June-July 2021) and analyzed for SARS-CoV-2 Spike protein (anti-S) and nucleocapsid (anti-N) antibodies using commercial antibody assays. 28 reactive samples were used to compare antibody levels with a pseudotyped neutralization assay. The results were further compared to the official national COVID-19 surveillance data to calculate the number of unreported cases. In total, n=2,626 individual blood samples were analyzed. In this unvaccinated pediatric cohort anti-S and anti-N antibody seroprevalence increased over the three time periods (anti-S: 1.38-9.16%, and 14.59%; anti-N: 1.26%, to 6.19%, and 8.56%). Compared to the national surveillance data this leads to a 3.93-5.66-fold increase in the number of unreported cases. However, a correlation between the cumulative incidence of the individual provinces and our assigned data was found (r=0.74, p=0.0151). In addition, reactive samples with anti-S and anti-N and samples with only anti-S showed neutralization capabilities (11/14 and 8/14, respectively). Anti-S levels were not significantly different between age groups and sexes (all p>0.05). The present study suggests that residual blood samples from routine laboratory chemistry could be included in the estimation of the total SARS-CoV-2 seroprevalence in children.

Investigation of the effects of pneumatic tube transport system on routine biochemistry, hematology, and coagulation tests in Ankara City Hospital.

Academics are far from a consensus regarding the effects of pneumatic tube system (PTS) delivery on sample integrity and laboratory test results. As for the reasons for conflicting opinions, each PTS is uniquely designed, sample tubes and patient characteristics differ among studies. This study aims to validate the PTS utilized in Ankara City Hospital for routine chemistry, coagulation, and hematology tests by comparing samples delivered via PTS and porter. The study comprises 50 healthy volunteers. Blood samples were drawn into three biochemistry, two coagulation, and two hemogram tubes from each participant. Each of the duplicate samples was transferred to the emergency laboratory via Swiss log PTS (aka PTS-immediately) or by a porter. The last of the biochemistry tubes were delivered via the PTS, upon completion of coagulation of the blood (aka PTS-after). The results of the analysis in these groups were compared with multiple statistical analyses. The study did not reveal any correlation between the PTS and serum hemolysis index. There were statistically significant differences in several biochemistry tests. However, none of them reached the clinical significance threshold. Basophil and large unidentified cell (LUC) tests had poor correlations (r=0.47 and r=0.60; respectively) and reached clinical significance threshold (the average percentages of bias, 10.2%, and 15.4%, respectively). The remainder of the hematology and coagulation parameters did not reach clinical significance level either. The modern PTS validated in this study is safe for sample transportation for routine chemistry, coagulation, and hematology tests frequently requested in healthy individuals except for basophil and LUC.

Evaluation and management of leukolysis-mediated pseudohyperkalemia in paediatric leukemic samples.

IntroductionLeukolysis-related pseudohyperkalemia due to preanalytical procedures may lead to erroneous (or absence of) treatment based on an invalid lab test result. We aimed to obtain a leukocyte threshold above which leukolysis-related pseudohyperkalemia becomes clinical relevant. Secondly, temporal dynamics of treatment-induced leukocyte decrease were studied to allow tailored implementation of laboratory information system (LIS) decision rules based on the leukocyte threshold to avoid leukolysis-related pseudohyperkalemia.Materials and methodsPotassium results of AU5811 routine chemistry (Beckman Coulter, Brea, California, USA) and iStat point of care (POC) (Abbott Diagnostics, Chicago, Illinois, USA) analysers were compared, the latter method being insensitive to leukolysis caused by pre-analytical procedures. Potassium results were combined with leukocyte counts obtained using a Cell-Dyn Sapphire haematology analyser (Abbott Diagnostics, Santa Clara, California, USA), resulting in 132 unique data triplets. Regression analysis was performed to establish a leukocyte threshold. The Reference Change Value (√2 x Z x √(CVa2 + CVi2)) was used to calculate maximum allowable difference between routine analyser and POC potassium results (deltamax + 0.58 mmol/L). Temporal analysis on the treatment-induced leukocyte decrease was performed by plotting leukocyte counts in time for all patients above the threshold leukocyte count (N = 41).ResultsEstablished leukocyte threshold was 63 x109/L. Temporal analysis showed leukocyte counts below the threshold within 8 days of treatment for all patients.ConclusionsBased on performed analyses we were able to implement LIS decision rules to reduce pseudohyperkalemia due to preanalytical procedures. This implementation can contribute to a reduction in erroneous (or absence of) treatments in the clinic.

Serum Metabolomics in Patients with Coexisting NAFLD and T2DM Using Liquid Chromatography-Mass Spectrometry.

Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) frequently coexist and can act synergistically to drive adverse outcomes of one another. This study aimed to unravel the metabolomic changes in patients with NAFLD and T2DM, to identify potential noninvasive biomarkers, and to provide insights for understanding the link between NAFLD and T2DM. Three hundred participants aged 35 to 70 years who were diagnosed with NAFLD (n = 100), T2DM (n = 100), or a comorbidity of NAFLD and T2DM (n = 100) were included in this study. Anthropometrics and routine blood chemistry were assessed after overnight fast. The global serum metabolomic analysis was performed by ultra-performance liquid chromatography-Orbitrap mass spectrometry. Multivariate data analysis methods were utilized to identify the potential biomarkers. A set of serum biomarkers that could effectively separate NAFLD from NAFLD + T2DM and T2DM from NAFLD + T2DM were identified. We found that patients with coexisting NAFLD and T2DM had significantly higher levels of total protein (TP), triglycerides (TG), glucose in urine, and gamma-hydroxybutyric acid than those with NAFLD and had significant increased levels of TP, albumin, alanine aminotransferase, aspartate aminotransferase, total cholesterol, cholinesterase, TG, low-density lipoprotein, and apolipoprotein A when compared to patients with T2DM. The metabolomics results provide evidence that the comorbidity of NAFLD and T2DM considerably altered patients' metabolomics patterns compared to those of patients with only NAFLD or T2DM.

A novel device for serial venous blood sampling in a canine model

Diagnostic serial venous blood sampling has the potential to introduce stress-related artifactual elements into the analytical results. We have evaluated the use of a wearable automated serial blood sampling device in a canine model that obviates a need for multiple manual venipuncture. Efficacy in measuring cortisol levels during prolonged serial blood sampling is described. Automated serial blood sampling from the jugular vein was performed in two Beagle dogs. Over two separate 22-h periods, serial blood samples were withdrawn for routine cell counting and blood chemistries from each animal, whilst animal behavior along with durability of catheter placement and tolerability by the vascular system were assessed.During the study, no behavioral changes attributed to the serial blood sampling device were seen and no stress-related deviations from normal blood cell counts and cortisol levels were detected. Minor erythema was eident at the sites of catheter placement, which was consistent with the presence of an indwelling catheter. The wearable, serial blood sampling device performed well and was tolerated by the animals without stress-related changes in blood analysis or behavioral observation. This study has demonstrated the potential significant benefit of the Fluispotter® device for serial blood sampling in veterinary and clinical settings. The samples collected are free from stress-related signatures in blood chemistry otherwise common to serial blood sampling protocols requiring repeated venipuncture. This device has valuable implications for use in routine preclinical pharmacology and toxicology studies.

Acute kidney injury secondary to obstetric complications in the third trimester of pregnancy and the puerperium

Background Acute kidney injury (AKI) in pregnancy is still a frequent health problem in developing countries. The aim of our study is to assess the prevalence and outcome of AKI secondary to obstetric complications during the third trimester of pregnancy and the puerperium Patients and methods A retrospective study conducted on 80 patients presented with AKI secondary to obstetric complications during the third trimester of pregnancy and the puerperium. All patients were recruited from the National Institute of Nephrology and Urology in Cairo during the period from June 2014 to June 2016. Data was collected from the unit database and patient medical charts including patient's history and examination findings during admission, laboratory parameters on admission including complete blood count and routine chemistry, hospital course, treatment received including renal replacement therapy and maternal and fetal outcomes. Results Our observational study included 80 patients presented with AKI during late pregnancy and the puerperium. Mean maternal age was 32±6 years and mean gestational age at presentation was 27±9 weeks. Mean serum creatinine was 7.7±2.4 mg/dl. Most of the patients who developed AKI did not receive antenatal care 67.5% (n=54). Also, more than half of the patients had a previous history of preeclampsia 52.5% (n=42). The median duration of hospital stay was 13 (6–51 interquartile range) days. Five (6%) patients underwent renal biopsy; 55 (69%) patients received hemodialysis as a renal replacement therapy while five patients received plasma exchange. The main etiology of AKI in our study was ischemic acute tubular necrosis 50% (n=40). Five (8%) patients developed chronic kidney disease and three patients (4%) progressed to end-stage renal disease. Maternal mortality was 4% (n=3) and fetal mortality was 74% (59 fetus). Conclusion AKI in late pregnancy and puerperium still presents as a health problem in developing countries. Most patients with AKI had a history of preeclampsia. Also, most of them had not received proper antenatal care. Improvement of the antenatal care is crucial for early detection and prevention of such problems.

Assessment of Total Laboratory Errors in Clinical Chemistry Laboratory: Experience at a Tertiary Care Hospital

Background: Efficient Laboratory services are the backbone of the modern healthcare facility. 70% of all medical decisions are based on laboratory data. We need to assess errors in the testing process to reduce their negative effect on patient outcomes and the entire healthcare sector. Objective: To assess Total Laboratory Errors (Pre-analytical, analytical, post-analytical) in the clinical chemistry laboratory. Materials and Methods: This cross-sectional study was conducted in Clinical Chemistry Laboratory, Sheikh Zayed Hospital, Rahim Yar Khan from 1st January to 30th June 2021. All blood samples received in Chemical Pathology Section for routine chemistry analysis in 6 months were included in the study using a consecutive sampling technique. 61891 blood samples were assessed for the following pre-analytical errors: Hemolysis, icterus, lipemia, incorrect order of draw, insufficient quantity, wrong tube, mislabeled specimen, missed patient information. Analytical errors were a violation of westgard rules while post-analytical errors included uninformed critical results, prolonged turnaround time and data transcription errors. Urine &amp; other body fluids such as cerebrospinal fluid (CSF), ascitic fluid, pleural fluid, pericardial fluid received for chemical analysis were excluded. Data analysis was done using SPSS 16. Results: Out of the total laboratory errors 5574, pre-analytical errors were the most frequently occurring errors 4512 (80.95%) followed by post-analytical errors 1017 (18.25%) &amp; analytical errors 45 (0.80%). The most frequently occurring pre-analytical error was hemolysis (64.38% of 80.95%). The most frequently occurring post-analytical error was uninformed critical results (70.79% of 18.25%). Conclusion: Pre-analytical errors have the highest percentage in total lab errors followed by post-analytical errors. Errors in the analytical phase are less due to Internal Quality Control &amp; laboratory automation.

371. Estimating SARS-CoV-2 Seroprevalence from Spent Blood Samples, January–March 2021

BackgroundMeasuring SARS-CoV-2 antibody prevalence in spent samples at serial time points can determine seropositivity in a diverse pool of individuals to inform understanding of trends as vaccinations are implemented.MethodsBlood samples collected for clinical testing and then discarded ("spent samples") were obtained from the clinical laboratory of a medical center in Atlanta. A convenience sample of spent samples from both inpatients (medical/surgical floors, intensive care, obstetrics) and outpatients (clinics and ambulatory surgery) were collected one day per week from January-March 2021. Samples were matched to clinical data from the electronic medical record. In-house single dilution serological assays for SARS-CoV-2 receptor binding domain (RBD) and nucleocapsid (N) antibodies were developed and validated using pre-pandemic and PCR-confirmed COVID-19 patient serum and plasma samples (Figure 1). ELISA optical density (OD) cutoffs for seroconversion were chosen using receiver operating characteristic analysis with areas under the curve for all four assays greater than 0.95 after 14 days post symptom onset. IgG profiles were defined as natural infection (RBD and N positive) or vaccinated (RBD positive, N negative). Figure 1. Nucleocapsid serology assay validation Single dilution serological assays for SARS-CoV-2 nucleocapsid antibodies were validated using pre-pandemic and PCR-confirmed COVID-19 patient serum and plasma samples. ELISA optical density (OD) cutoffs for seroconversion were chosen using receiver operating characteristic (ROC) analysis with areas under the curve (AUC) for all four assays greater than 0.95 after 14 days post symptom onset.ResultsA total of 2406 samples were collected from 2132 unique patients. Median age was 58 years (IQR 40-70), with 766 (36%) ≥ 65 years. The majority were female (1173, 55%), and 1341 (63%) were Black. Median Elixhauser comorbidity index was 5 (IQR 2-9). 210 (9.9%) patients ever had SARS-CoV-2 detected by PCR, and 191 (9.0%) received a COVID-19 vaccine within the health system. Nearly half (1186/2406, 49.3%) of samples were collected from inpatient units, 586 (24.4%) from outpatient labs, 403 (16.8%) from the emergency department, and 231 (9.6%) from infusion centers. Overall, 17.0% had the IgG natural infection profile, while 16.2% had a vaccination profile. Prevalence estimates for IgG due to natural infection ranged from 24.0% in week 2 to 9.7% in week 5, and for IgG due to vaccine from 4.4% in week 2 to 32.0% in week 6 (Table, Figure 2).Table. SARS-CoV-2 antibody seropositivity by week of sample collection for spent routine blood chemistry samples. RBD = receptor binding domain. N = nucleocapsid. Seropositivity defined by enzyme-linked immunoassay (ELISA) optical density cutoffs selected using receiver operating characteristic analysis with areas under the curve (AUC) for all four assays greater than 0.95 after 14 days post symptom onset. IgG defined as positive if both RBD and N seropositive.Figure 2. RBD and Nucleocapsid seropositivity to differentiate natural infection vs. vaccination by week of sample collection. RBD = receptor binding domain. N = nucleocapsid. Seropositivity defined by enzyme-linked immunoassay (ELISA) optical density cutoffs selected using receiver operating characteristic analysis with areas under the curve (AUC) for all four assays greater than 0.95 after 14 days post symptom onset.ConclusionEstimated SARS-CoV-2 IgG seroprevalence among patients at a medical center from January-March 2021 was 17% by natural infection, and 16% by vaccination. Weekly trends likely reflect community spread and vaccine uptake. Disclosures Daniel Graciaa, MD, MPH, MSc, Critica, Inc (Consultant)

Museum-archived and recent acquisition nitrates from the Atacama Desert, Chile, South America: refinement of the dual isotopic compositions (δ 15N vs. δ 18O)

ABSTRACT Sodium nitrate ores from the Atacama Desert in South America were economically important as they represented huge natural resources for the fertilizer and explosives industries during the early nineteenth to early twentieth centuries. Nitrogen and oxygen isotope ratios (δ 15N and δ 18O) of these desert nitrates generally show unique compositions (from close to 0 and up to ca. +50 ‰, respectively). The nitrates indicate the provenance as atmospheric in origin due to the mass-independent photochemical reaction of nitric oxide (NO) with ozone (O3) in the atmosphere to produce nitrate (NO3 –). This paper examines the previously existing isotope data for specimens acquired from the Atacama Desert. It then reports new data from dual isotope analysis of historic nitrate specimens archived in museums in the UK. In the stable isotope signatures for nitrates from two areas of the Atacama Desert, Tarapacá in the north and Antofagasta in the south, were examined, and this analysis enabled a more detailed definition of their isotopic compositional ranges. This improved database is useful for tracing the provenance of the historic nitrates used in gunpowder and saltpetre, and also the cause of nitrate pollution in natural environments for which routine chemistry alone cannot provide the definite evidence for the origin.

Assessment of Sigma Metrics for Routine Chemistry Testing in 4 Laboratories in Kwa-Zulu Natal, South Africa

Sigma metrics is a quantitative management tool. This study assessed the Six Sigma score for 26 chemistry analytes, compared scores with different total allowable errors (TEa) and use of scores for internal quality control (IQC) rules in 4 Laboratories in Kwa-Zulu Natal, South Africa. Utilizing 6 months of IQC SD, CV, and bias data on albumin, alkaline phosphatase, alanine aminotransferase, amylase, aspartate aminotransferase, bicarbonate, calcium, total cholesterol, creatine kinase, chloride, creatinine, gamma glutamyl transferase, glucose, HDL-cholesterol, potassium, lactate dehydrogenase, magnesium, sodium, inorganic phosphate, direct bilirubin, total bilirubin, triglycerides, total protein, urea nitrogen, uric acid, and C-reactive protein (CRP) Six Sigma scores were calculated using Microsoft Excel 2016 and ideal IQC rules were determined. Six Sigma scores using Ricos et al. 2014, Royal College of Pathologists Australasia, and Clinical Laboratory Improvement Amendments TEas were compared. For levels 1, 2, and 3 respectively, analytes scoring >3 sigma was 9 (35%), 12 (46%), and 14 (54%) in Laboratory A; Laboratory B had 15 (58%), 19 (73%), and 17 (65%); Laboratory C had 12 (46%), 13 (50%), and 15 (58%); and Laboratory D had 13 (50%), 18 (69%), and 18 (69%). Albumin, calcium, sodium, magnesium, bicarbonate, and chloride scored <3; CRP scored >6 for all. In Laboratories A, B, C, and D, 7 (27%), 7 (27%), 6 (23%), and 8 (31%) analytes, respectively, required only 1 IQC rule. One of 21 analytes for Laboratories C and D, 3 for Laboratory A, and 0 for Laboratory B had the same sigma score with all 3 databases. Despite South Africa being a developing nation, many analytes are able to achieve >3 sigma.