Clinical chemistry最新文献

{"title":"B-001 Serum 25-hydroxyvitamin D and C-3 epimer concentrations throughout gestation in a bovine dairy herd","authors":"J P Buchweitz, S Velasquez Rivertte, J A Zyskowski, A Abuelo Sebio","doi":"10.1093/clinchem/hvae106.365","DOIUrl":"https://doi.org/10.1093/clinchem/hvae106.365","url":null,"abstract":"Background Serum 25-hydroxyvitamin D (25(OH)D) serves as an indicator of vitamin D status in most animal species. The recent identification of its C-3 epimer, 3-epi-25-hydroxyvitamin D3 (3-epi-25(OH)D3) remains diagnostically confounding. The appearance of this epimer in blood serum has been reported for both pregnant women and infants; however, because of its recent discovery, its physiologic role, biochemical regulation, and overall biologic importance have yet to be fully elucidated. Given its prevalence in pregnant women, it was hypothesized that 3-epi-25(OH)D3 may serve as a novel predictive biomarker of pregnancy in animals. Methods In the current study, we validated an LC-MS/MS method to measure the mono-hydroxyvitamin D metabolites 25-hydroxyvitamin D2 (25(OH)D2), 25-hydroxyvitamin D3 (25(OH)D3), and 3-epi-25(OH)D3, in bovine serum. Serum was collected from dairy cows at six stages of pregnancy (n=60 (10 per group), pre-breeding heifers, 30-40 days pregnant, 70-90 days, 120-180 days, 210-260 days, and 30-45 days post-calving). The 25(OH)D metabolites were extracted from serum by supported liquid extraction (SLE) and the eluate was derivatized with 2-Nitrosopyridine. Derivatized samples were introduced to the LC-MS/MS, ionized by electrospray ionization in positive-ion mode, and detected and quantified by multiple-reaction monitoring. Results The LC-MS/MS method was linear in the concentration range of 0.25 ng/mL to 100 ng/mL with an r2 > 0.99 for each analyte. 3-epi-25(OH)D3 and total serum 25(OH)D concentrations were calculated for each stage of pregnancy. Pre-bred heifers had serum 25(OH)D concentrations ranging from 65 - 85 ng/mL with trends toward non-significant increases with mean values approaching 100 ng/mL during pregnancy. Interestingly, 3-epi-25(OH)D3 remained near baseline (1.3 - 1.9 ng/mL) for the first 90 days and elevated 3- to 4-fold thereafter. Conclusions This study confirms that epimerization of 25(OH)D3 is a conserved biochemical process across species. While not predictive of pregnancy itself, the increase in circulating 3-epi-25(OH)D3 concentrations was consistent with mid- to late-gestational increases in estrogen concentration observed for dairy cattle. Future studies will explore the potential link between increases in gestational estrogen and epimerization.","PeriodicalId":10690,"journal":{"name":"Clinical chemistry","volume":"48 1","pages":""},"PeriodicalIF":9.3,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142362936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"B-018 Design and Development of MASTM Diabetes Max Controls, Ready-to-Use Plastic Tube Format","authors":"M Nagaraj, D Crandall, M Kasprisin, N Adams, J Shah, A Qureshi, R Hu","doi":"10.1093/clinchem/hvae106.382","DOIUrl":"https://doi.org/10.1093/clinchem/hvae106.382","url":null,"abstract":"Background The Thermo Scientific™ MAS™ Controls are assayed controls to monitor assay performance within clinical laboratory settings. The user can compare observed results of controls with their expected ranges as a means of assuring consistent performance of both reagent and instrument. The objective of developing MAS™ Ready-to-Use Tube Controls is to provide MAS™ controls in a new automation-friendly plastic tube format, as an alternative to the current glass vials. Diabetes Max Control is the first MAS™ product designed and developed in this ready-to-use format to be placed directly on the analyzer. The new format will increase efficiency and allow for on-board refrigerated storage, and it is expected to reduce material loss and contamination. It contains Hemoglobin A1c formulated in whole blood matrix to mimic patient specimens. In this presentation we summarize the Feasibility, Development, Verification, and Validation results of MAS™ Diabetes Max Controls. Methods The performance was assessed by conducting the following studies for MAS™ Diabetes Max Tube Controls. The analyte Hemoglobin A1c was measured in functional studies to evaluate and verify the product performance. Other studies were also designed and performed to assess the product usability. Results MAS™ Diabetes Max Control results demonstrated comparable performance and Fit/Form/Function criterion on specified platforms, particularly the TOSOH™ platform. All feasibility studies provided very promising results passing per protocol criterion. Design Verification and Validation studies ensured product integrity and passed specifications for proposed claims. Process Validation is in progress with data being collected for both Value Assignments and Real Time Stability. Conclusions MAS™ Diabetes Max Controls provided in ready-to-use tubes met the design specification criteria. We believe that MAS™ Diabetes Max Controls will contribute to the increased efficiency of core lab workflow by allowing the analyzer(s) to aspirate controls directly from the tube and allow for control storage in an on-board refrigeration unit.","PeriodicalId":10690,"journal":{"name":"Clinical chemistry","volume":"220 1","pages":""},"PeriodicalIF":9.3,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142362858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"B-033 Real World Assessment of the Impact of Infectious Disease Assays on Workflow Capabilities of Siemens Atellica IM Analyzers","authors":"C Abou-Diwan, R Hempton, J Clouet, D Diabate, J Aguanno","doi":"10.1093/clinchem/hvae106.397","DOIUrl":"https://doi.org/10.1093/clinchem/hvae106.397","url":null,"abstract":"Background Instrument immunoassay throughputs publicized in the industry are often theoretical, performed in relatively smaller scale, and/or in the best case generated only with fast assays, not representing the typical assay mix of routine activity. Infectious disease (ID) serology assays typically have long analytical times and have the potential to influence throughput capabilities and turnaround time (TAT) of other assays with shorter analytical times. The objective of this study is to utilize real world evidence across a large fleet of Atellica® IM 1300 and IM 1600 analyzers representing variously sized laboratories, using variations of ID assay mixes, to assess the impact on TAT on select STAT immunoassays. Methods Assay mix, test volumes and TAT data was mined from the Atellica® Smart Remote Services (SRS), a Siemens Healthineers proprietary remote connectivity platform over 3 distinct 14-day time windows. Real world data from >1800 Atellica IM and >8 million tests were queried per time window for the following ID assays: HIV, Hepatitis B, Hepatitis C, TORCH, Syphilis (long analytical time) and a selection of non-ID immunoassays: hs-troponin I (TNIH), Thyroid Stimulating Hormone (TSH3UL), total HCG (ThCG), and B-Type Natriuretic Peptide (BNP) (short analytical time). Median TAT for short assay was analyzed with 6 variations of ID assay mix (0%, <10%, <20%, <30%, <40%, <50%) in the run representing increasing percentages of assays requiring longer incubation times. TAT was represented as barcode to result and aspiration to result. Results The median TAT for TNIH remained consistent at 10.1 minutes across increasing % of ID assays (N=100961). The median TAT for TNIH for platforms not running ID assays (83237) remained consistent at 10.03 minutes. The median TAT for TSH remained consistent at 14.02 minutes across increasing % of ID assays (N=1183344). The median TAT for TSH for platforms not running ID assays (N=480219) remained consistent at 13.98 minutes. The median TAT for ThCG remained consistent at 10.28 minutes across increasing % of ID assays (N=24677). The median TAT for ThCG for platforms not running ID assays (N=79275) remained consistent at 10.27 minutes. The median TAT for BNP remained consistent at 10.1 minutes across increasing % of ID assays (N=42949). The median TAT for BNP for platforms not running ID assays (N=14990) remained consistent at 10.03 minutes. Conclusions Throughput and TAT on the Atellica IM Analyzer is relatively unaffected by mix of longer-incubation and shorter-incubation assays. The dual incubation rings allow more flexibility in the mix of incubation times with predictable and consistent TAT for all assays including STAT.","PeriodicalId":10690,"journal":{"name":"Clinical chemistry","volume":"57 1","pages":""},"PeriodicalIF":9.3,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142362859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A-349 Evaluation of i-STAT® Point of Care Blood Gas Cartridges and Competitor Blood Gas Devices Against Reference Standard for PCO2 and PO2","authors":"C Beattie, L Thibodeau","doi":"10.1093/clinchem/hvae106.343","DOIUrl":"https://doi.org/10.1093/clinchem/hvae106.343","url":null,"abstract":"Background The i-STAT System provides laboratory quality results in minutes at the patient’s bedside. Accurate and rapid test results are critical for clinical decision making in the presence of blood gas disorders, including oxygenation and acid-base status, where the partial pressure oxygen (PO2) and partial pressure carbon dioxide (PCO2) are needed. The purpose of this study was to compare the analytical performance of the PO2 and PCO2 tests in the i-STAT G3+ and i-STAT CG8+ cartridges to the theoretical PO2 and PCO2 in prepared reference standards. Two other blood gas instruments, a benchtop device and a laboratory device were also compared to the reference PO2 and PCO2. Methods Venous whole blood samples were contrived using saturation tonometry with U.S. NIST (National Institute of Science and Technology) traceable gas tanks to prepare the reference standards, which were value assigned to theoretical PO2 or PCO2 levels based on the molar composition of the gas mixture used. Eleven levels spanning the reportable range of each PO2 (5 mmHg - 800 mmHg) and PCO2 (5 mmHg - 130 mmHg) were prepared and tested in duplicate on the i-STAT G3+ and i-STAT CG8+ cartridges, benchtop device, and the laboratory device. Passing-Bablok linear regression analysis was performed to evaluate the slope and correlation coefficient, comparing each blood gas device against the reference PO2 and PCO2 values. Study designs followed CLSI (Clinical and Laboratory Standards Institute) EP09C-ED3:2018, Measurement Procedure Comparison and Bias Estimation using Patient Samples, 3rd Edition. Passing-Bablok regression analysis was also performed for the i-STAT cartridges and benchtop device against the laboratory device. Results The regression analysis was performed against the reference standards. For PO2, slopes for the i-STAT cartridges ranged from 0.93 - 0.97, the slope for the benchtop device was 0.99, and the slope for the laboratory device was 0.97. Correlation coefficients for all devices were 1.00. For PCO2, slopes for the i-STAT cartridges ranged from 0.98 - 1.02, the slope for the benchtop device was 0.85, and the slope for the laboratory device was 1.01. Correlation coefficients were 1.00 for the i-STAT cartridges and laboratory device, and 0.99 for the benchtop device. The regression analysis was also performed against the laboratory device. For PO2, slopes for the i-STAT cartridges ranged from 0.96 - 1.00, and the slope for the benchtop device was 1.02. Correlation coefficients for all devices were 1.00. For PCO2, slopes for the i-STAT cartridges ranged from 0.97 - 1.01, and the slope for the benchtop device was 0.85. Correlation coefficients were 1.00 for the i-STAT cartridges and 0.99 for the benchtop device. Conclusions The study demonstrated that the i-STAT G3+ and i-STAT CG8+ cartridges used with the i-STAT System were shown to provide laboratory quality results within 2 minutes, showing good agreement to both reference standards and laboratory quality devic","PeriodicalId":10690,"journal":{"name":"Clinical chemistry","volume":"24 1","pages":""},"PeriodicalIF":9.3,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142362965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A-354 Evaluating Emergent POC Technology for Sickle Cell Testing in Resource Limited Settings","authors":"E Schuler, J Mortensen, K Prus","doi":"10.1093/clinchem/hvae106.348","DOIUrl":"https://doi.org/10.1093/clinchem/hvae106.348","url":null,"abstract":"Background Sickle cell disease (SCD) represents a collection of inherited hematological disorders characterized by abnormal sickle-shaped erythrocytes resulting in an increased risk of morbidity and mortality. SCD represents a significant global health burden, affecting more than 300,000 newborns per year. Most of these births occur in resource limited areas, including sub-Saharan Africa, where the mortality rate before the age of five is estimated to be as high as 50-80% and the existing infrastructure and resources cannot support most current and robust methods that offer hemoglobin variant detection and quantification for the diagnosis and monitoring of SCD. While newborn screening programs (NBS) to identify individuals affected with SCD have demonstrated efficacy in reducing morbidity and early mortality, NBS programs are limited outside of the US and Europe and face many practical challenges for universal implementation in a resource limited setting. The need for inexpensive and reliable hemoglobin variant detection and quantification at the Point of Care is essential to the diagnosis and management of SCD in resource limited settings with a high prevalence of SCD, and the expansion of NBS programs. This study aims to evaluate an inexpensive testing strategy using two methodologies for POC screening and confirmation of SCD that could be supported in a low resource setting. Methods The two-step testing strategy for evaluation of POC testing for hemoglobin variant detection and quantification included testing residual specimens from normal and known sickle cell patients by first screening with the HemoTypeSC, a qualitative lateral flow immunoassay (LFIA) that has improved sensitivity and specificity from other available LFIA methodologies given the use of monoclonal antibodies for the detection of hemoglobin variants. Confirmatory testing and quantification of hemoglobin variants was accomplished with the use of the Gazelle POC test a miniaturized chip-based cellulose acetate electrophoresis device capable of identification and quantification of normal and variant hemoglobin. Statistical evaluation of device performance and clinical agreement between the device and known disease status was achieved in EP evaluator. Results The two-tier testing strategy demonstrated effective and inexpensive mechanism for SCD screening and confirmation. Overall, the HemoTypeSC and Gazelle demonstrated 100% qualitative agreement between methods, with the total cost of the two-tiered testing strategy estimated at under $6 per sample. Conclusions In conclusion, the two-tiered approach using the HemoTypeSC and Gazelle yielded a practical and cost-effective strategy for screening and confirmation of hemoglobin variants for the detection and monitoring of SCD. Both the strip and chip-based methodologies provide rapid results, are accessible at the point-of-care, and require minimal sample volume, a feature ideal for use in a pediatric population in low resource setti","PeriodicalId":10690,"journal":{"name":"Clinical chemistry","volume":"3 1","pages":""},"PeriodicalIF":9.3,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142362968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A-237 Analytical Performance Evaluation of Cytomegalovirus IgG and Syphilis Assays on the Atellica CI Analyzer","authors":"M Quintanilla, B Valdivia, L Halik, G Arrode-Bruses, H Leipold","doi":"10.1093/clinchem/hvae106.234","DOIUrl":"https://doi.org/10.1093/clinchem/hvae106.234","url":null,"abstract":"Background The Atellica® CI Analyzer is an automated, high-throughput integrated chemistry and immunoassay analyzer utilizing both Atellica® CH and Atellica® IM Assays. This study evaluated the analytical performance of the Atellica IM Cytomegalovirus IgG (CMV IgG) and Syphilis (Syph) Assays on the Atellica CI Analyzer. Methods Precision studies were performed according to CLSI EP05-A3 using native and contrived human serum samples. CMV IgG and Syph Assays were evaluated with one reagent lot on two Atellica CI analyzers. One aliquot of each sample was tested in duplicate in two runs per day ≥2 hours apart on each analyzer for ≥20 days. Method comparison studies were performed according to CLSI EP12-A2. Individual native human serum samples were analyzed using the Atellica IM CMV IgG and Syph Assays on the Atellica IM and Atellica CI Analyzers. The results were assessed based on Index values distinguishing reactive (Index ≥cut-off value) and nonreactive (Index <cut-off value) specimens. Results As shown in table below, repeatability and within-lab %CVs for the two assays presented were <3.7% and <7.0%. Negative and positive agreement were 100% for the 111 nonreactive CMV IgG samples and the 169 CMV IgG reactive samples tested. Negative and positive agreement were 100% for the 103 Syph reactive samples and the 126 nonreactive Syph samples tested. Overall clinical agreement between each of the presented assays on the Atellica CI Analyzer and Atellica IM Analyzer was 100%. Conclusions Evaluation of the Atellica IM CMV IgG and Syph Assays using the Atellica CI Analyzer demonstrated acceptable precision and equivalent performance compared to the same assays on the Atellica IM Analyzer.","PeriodicalId":10690,"journal":{"name":"Clinical chemistry","volume":"37 1","pages":""},"PeriodicalIF":9.3,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142369091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"B-263 Analytical Performance Evaluation of Eleven Drug of Abuse Assays on the Atellica CI Analyzer","authors":"S Lewisch, P Gupta, W Varhue, G Arrode-Bruses, J Snyder","doi":"10.1093/clinchem/hvae106.620","DOIUrl":"https://doi.org/10.1093/clinchem/hvae106.620","url":null,"abstract":"Background The Atellica® CI Analyzer is an automated, high-throughput integrated chemistry and immunoassay analyzer utilizing both Atellica® CH and Atellica® IM Assays. This study evaluated the analytical performance of the Atellica CH Amphetamines (Amp), Barbiturates (Brb), Benzodiazepine (Bnz), Cannabinoids THC (Thc), Cocaine Metabolite (Coc), Ecstasy (Xtc), Methadone (Mdn), Opiates (Op), Oxycodone (OXY), Phencyclidine (Pcp), and Propoxyphene (Ppx) Assays on the Atellica CI Analyzer. Methods Precision and method comparison (MC) studies were used as performance indicators. Precision studies were performed according to CLSI EP05-A3 using quality control (QC) samples consisting of contrived human urine samples. One aliquot of each QC was tested in duplicate in two runs per day ≥2 hours apart on each analyzer for ≥ 20 days. Precision for each assay was evaluated with one reagent lot on one system. Method comparison studies were performed with three reagent lots according to CLSI EP12-A2. Individual native and contrived human urine samples were analyzed using the Atellica CH Amp, Barb, Bnz, Thc, Coc, Xtc, Mdn, Op, OXY, Pcp, and Ppx Assays on both the Atellica CH and Atellica CI Analyzers. The results were assessed based on analyte values used for distinguishing positive (value ≥cutoff) and negative (value <cutoff) specimens. Results As shown in table below, repeatability and within-lab %CVs based on manufacturer arbitrary units (mAU) were <0.8% and <3.2%, respectively or qualitative interpretation for each replicate remained unchanged for all 80 precision testing measurements (OXY, PcP). Qualitative accuracy assessed by concordance analysis demonstrated ≥95% agreement between the Atellica CI Analyzer and Atellica CH Analyzer. Conclusions Evaluation of the Atellica CH Amp, Barb, Bnz, Thc, Coc, Xtc, Mdn, Op, OXY, Pcp, and Ppx Assays using the Atellica CI Analyzer demonstrated acceptable precision and equivalent performance compared to the same assays on the Atellica CH Analyzer.","PeriodicalId":10690,"journal":{"name":"Clinical chemistry","volume":"25 1","pages":""},"PeriodicalIF":9.3,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142369093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"B-047 A Rapid Host-Response Test Supports Antimicrobial Stewardship at a Micro-Hospital Emergency Department","authors":"B DuChateau, S Murphy, C Tarr, T Gottlieb, S Spies","doi":"10.1093/clinchem/hvae106.409","DOIUrl":"https://doi.org/10.1093/clinchem/hvae106.409","url":null,"abstract":"Background The management of patients with suspected infections requires identification of the infectious etiology to determine appropriate use of antibiotics. However, differentiating viral from bacterial infection (and co-infection) is often challenging as clinical presentations can be similar and existing diagnostics sometimes fail to identify a clinically relevant pathogen. A host-response test (MeMed BV®, MMBV) that relies on computational integration of three proteins (TRAIL, IP-10 and CRP) measured from blood or serum has demonstrated high diagnostic performance for differentiating bacterial from viral infections, with a negative predictive value >95% across multiple studies. This report evaluates real-world use of MMBV at a micro-hospital Emergency Department (ED) and associated antibiotic prescribing. Methods The study is a retrospective analysis of real-world data collected between January and June 2023. MMBV was ordered by providers at a micro-hospital ED in Tucson, AZ at provider discretion as part of routine care. Prescription among cases with MMBV score <35 was analyzed. This cutoff is indicated by the manufacturer to indicate a viral or other non-bacterial etiology. If an antibiotic was prescribed, the authors conducted a chart review to adjudicate whether the prescription was warranted. Results Data was evaluated between January and June 2023; 116 MMBV tests were ordered by six providers. Most tests (81.9% (95%CI: ±7.0%)) had an MMBV score <35 (mean score 11.3 with standard deviation 10.8). Among these, 92.6% (95%CI: ±5.3%) of cases with viral results were not prescribed antibiotics. MMBV use increased throughout the study period from 12 tests in the first month to 25 in the last month (r = 0.88; p<0.001). There were seven cases where providers chose to prescribe despite a viral MMBV result. Upon chart review, 2/7 were unwarranted prescriptions. Conclusions In the emergency settings, integrating MMBV can effectively guide clinical decision-making, potentially reducing unnecessary antibiotic use. Further research in diverse healthcare settings is needed to validate these findings.","PeriodicalId":10690,"journal":{"name":"Clinical chemistry","volume":"74 1","pages":""},"PeriodicalIF":9.3,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142368762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A-082 Establishment of Infant Free T4 Reference Interval Through Indirect Methods","authors":"Z Wu, C Bi, E M Li, E I Schindler, M I Marcelli, E C Wong, N J Clarke","doi":"10.1093/clinchem/hvae106.081","DOIUrl":"https://doi.org/10.1093/clinchem/hvae106.081","url":null,"abstract":"Background Children require reference intervals distinct from adults and, based on their unique developing physiology, several intervals are often required to accurately reflect the distribution of expected results in a healthy pediatric population. The establishment of pediatric reference intervals has proven challenging. While consenting adults volunteer to contribute their biological material towards the development of a reference interval, well children usually do not have the occasion to get blood drawn and the smaller the child, the more significant the impact of phlebotomy. For these reasons, scientists have sought out other methods for determining pediatric reference intervals. As an alternative, indirect statistical methods may be applied to large data sets of laboratory test results to ascertain a reference interval. The Multi-Modal Decomposition (MMD) is an iterative indirect method that decomposes a mixture of multiple normal distributions into separate components using the expectation-maximization (EM) algorithm The objective of the current study, was to apply MMD to ascertain reference intervals for free T4 in infants. Methods The study population included infants ranging in age from 1 day to 60 days who had specimens submitted for free T4 testing involving equilibrium dialysis followed by LC-MS/MS in a commercial reference laboratory (Quest Diagnostics Nichols Institute, San Juan Capistrano, CA). MMD was performed on 25,271 de-identified free T4 results to establish the reference intervals that were validated by comparison against free T4 values obtained on 238 de-identified specimens submitted for acylcarnitine testing, the specimen were analyzed for TSH and only the in-range specimens were include for Free T4 reference interval analysis. Results MMD analysis demonstrated distinct reference intervals for the following ages: 0 to 6 days (1.8 - 6.1 ng/dL), 7 days to <2 weeks (1 - 4.4 ng/dL), 2 to <3 weeks (0.8 - 3.5 ng/dL), 3 to <4 weeks (0.8 - 3 ng/dL), and 4 to <8 weeks (0.7 - 2.8 ng/dL). The data did not support the use of separate intervals for male and female children. Conclusions MMD analysis demonstrated distinct reference intervals for the following ages: 0 to 6 days (1.8 - 6.1 ng/dL), 7 days to <2 weeks (1 - 4.4 ng/dL), 2 to <3 weeks (0.8 - 3.5 ng/dL), 3 to <4 weeks (0.8 - 3 ng/dL), and 4 to <8 weeks (0.7 - 2.8 ng/dL). The data did not support the use of separate intervals for male and female children.","PeriodicalId":10690,"journal":{"name":"Clinical chemistry","volume":"26 1","pages":""},"PeriodicalIF":9.3,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142368787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"B-004 Method Validation of Lactate in the Plasma of Rats","authors":"A Sringeri, A Kalb","doi":"10.1093/clinchem/hvae106.368","DOIUrl":"https://doi.org/10.1093/clinchem/hvae106.368","url":null,"abstract":"Background The objective of this study is to validate Lactate (LAC) measurement in rat plasma using the ADVIA 1800 analyzer. Methods LAC was validated in rat plasma using the ADVIA 1800 analyzer. Validation testing included intra-assay and inter-assay precision, accuracy, linearity of dilution, limit of quantitation (LOQ), limit of detection (LOD), reference interval, carry-over, correlation, recovery, and stability. Samples were collected into tubes containing sodium fluoride. Intra-assay precision was determined by analyzing two biological samples and the two quality control levels of Bio-Rad Lyphochek Assayed Chemistry Control 10 consecutive times. Inter-assay precision was determined by analyzing the two quality control levels in duplicate for six days over a 10-day period. Accuracy was calculated using the data obtained from the inter-assay precision testing. For linearity of dilution, Audit MicroControl General Chemistry Linearity Kit and biological samples were diluted and analyzed in duplicate. The LOQ was determined by diluting the calibrator material to produce a value at the low end of the reportable range. Diluted material was tested six times. The LOD was determined by assaying the appropriate blank 10 times. The reference interval was determined by analyzing 21 plasma samples. Correlation between the two ADVIA 1800 analyzers was determined by assaying 10 samples on both analyzers once. The carry-over of the assay was determined by analyzing the high-level quality control material followed by the low-level quality control material. Recovery was determined by analyzing a pair of test samples in duplicate that have been spiked and diluted. The proportional error between the two test samples was calculated. Stability of plasma samples was tested on wet ice, refrigerated, and frozen (at -70°C) for various durations of storage. Results Measurement of LAC in rat plasma met the acceptance criteria for precision, accuracy, linearity of dilution, limit of quantitation, carry-over, recovery, and stability. For intra-assay precision in specimen and control material, the %CV was within ±20%. The inter-assay precision %CV was within ±20%. The total error observed (TEobs) was within ±20% for accuracy and the obtained mean of the control material was within the manufacturer’s acceptable range. For linearity of dilution, the coefficient of determination was ≥ 0.9000, the slope was within 1.00 ± 0.25, and TEobs for each plasma and linearity kit dilution was ≤20%. The LOQ was set at the lowest concentration for which the TEobs was within ±20%. The LOD was calculated by adding the mean concentration obtained and three times the standard deviation. The reference interval was set to the 2.5th to 97.5th percentile interval using Excel software. The carry-over was acceptable at ≤2%. Correlation between the two ADVIA 1800 analyzers was determined to describe any bias in result interpretation. Recovery was acceptable as the proportional error was within ±20%","PeriodicalId":10690,"journal":{"name":"Clinical chemistry","volume":"29 1","pages":""},"PeriodicalIF":9.3,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142363002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}