Annals of Clinical Biochemistry最新文献

{"title":"Pseudohyperphosphatemia induced by endogenous lipoproteins: New elements supporting an interference with ammonium phosphomolybdate-based methods.","authors":"Charles R Lefèvre, Felipe Le Divenah, Bastien Paterek, Kubra Cankaya, Martine Ropert-Bouchet, Emmanuelle Letourneux, Maxime Pawlowski, Nicolas Collet, Claude Bendavid","doi":"10.1177/00045632251342084","DOIUrl":"https://doi.org/10.1177/00045632251342084","url":null,"abstract":"<p><p>BackgroundInorganic phosphate (Pi) is a crucial electrolyte for maintaining homeostasis. Most methods measure Pi using ammonium phosphomolybdate under highly acidic conditions. Phospholipid-rich substances, such as liposomal amphotericin B, have been previously reported to artificially elevate Pi levels due to phospholipid hydrolysis in the acidic medium. This study aimed to investigate whether endogenous lipoproteins interfere with Pi measurement in cases of hyperlipidemia.MethodsWe conducted a retrospective study comparing mean Pi levels in 194,636 patients divided in groups with varying degrees of lipemia. Additionally, we performed a prospective study involving 85 patients presenting a range of lipemia to evaluate changes in Pi levels before and after plasma high-speed centrifugation-filtration, which retains all endogenous lipoproteins.ResultsThe retrospective study revealed a significant increase in Pi levels in relation with the degree of lipemia (<i>P</i> < .0001). The prospective study demonstrated a significant decrease in phosphatemia (<i>P</i> < .0001), with mean Pi levels of 1.36 mmol/L (4.22 mg/dL) before filtration and 1.27 mmol/L (3.94 mg/dL) after filtration, representing a mean decrease of 6.8%. Furthermore, the bias, defined as 100*(([Pi]_before - [Pi]_after)/[Pi]_before), was correlated with the lipemia level (r = 0.34, <i>P</i> = .001).ConclusionsThis study confirms that hyperlipidemia induces an analytically significant pseudohyperphosphatemia in a lipemia-dependent manner.</p>","PeriodicalId":8005,"journal":{"name":"Annals of Clinical Biochemistry","volume":" ","pages":"45632251342084"},"PeriodicalIF":2.1,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143956433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of pH on stability and solid phase extraction of urinary free metadrenaline measurement by liquid chromatography tandem mass spectrometry.","authors":"Lindsay McDonald, Craig Livie, Karen Smith, Susan Johnston","doi":"10.1177/00045632251342098","DOIUrl":"https://doi.org/10.1177/00045632251342098","url":null,"abstract":"<p><p>BackgroundMeasurement of urine free metadrenalines offers potential diagnostic and practical advantages over urinary fractionated metadrenalines in detection of phaeochromocytoma and paraganglioma, including sample collection without acid preservative. Here, we evaluate stability with and without sample acidification as well as pH implications for analysis by solid-phase extraction (SPE) and liquid chromatography tandem mass spectrometry.MethodsSpot urine samples were adjusted to pH 3 or unacidified on day of collection and stored at room temperature, 4°C or -20°C, for up to 28 days to assess changes in free metadrenaline concentrations over time. Extraction of unacidified versus acidified urine was examined by comparing peak areas and measuring concentrations present in sample eluents according to two SPE methodologies.ResultsFree metadrenalines remained stable in urine with or without acidification for up to 28 days, with mean reduction in concentrations of <10% for all storage conditions. Measured concentrations progressively increased without acidification at room temperature at low concentrations but remained constant when spiked with pathological concentrations. Peak areas were up to 97-fold lower in acidified than unacidified samples when extracted using weak cation exchange (WCX). On average 64% of analyte eluted in the flowthrough in acidified samples relative to 1.5% without acidification. By contrast, over 99% was retained in the extract using polar extraction at either pH.ConclusionUrine free metadrenalines remain stable at room temperature for up to 28 days and are more efficiently extracted without use of acid preservative if using WCX methodology.</p>","PeriodicalId":8005,"journal":{"name":"Annals of Clinical Biochemistry","volume":" ","pages":"45632251342098"},"PeriodicalIF":2.1,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143966513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance of the Binding Site cerebrospinal fluid kappa free light chains assay.","authors":"Simon Alfred Handley, Suzanne Barnes, Nicole Jenkins, Troy Wanandy","doi":"10.1177/00045632251337616","DOIUrl":"https://doi.org/10.1177/00045632251337616","url":null,"abstract":"<p><p>BackgroundMeasurement of cerebrospinal fluid (CSF) kappa free light chains (KFLCs) for the detection of intrathecal immunoglobulin synthesis has generated interest as an alternative to CSF oligoclonal bands due to its rapid turnaround time and ability to automate the assay. A turbidimetric immunoassay - Freelite Mx, is available from the Binding Site, but published data on performance is scant. Therefore, we undertook a multicentre sample comparison and investigated reagent lot-to-lot-variation (LTLV).MethodsIntra-/inter-assay accuracy and imprecision of the Freelite Mx assay on the Binding Site Optilite analyser was assessed. Twenty paired CSF/serum samples were sent to three laboratories within Australia for the measurement of CSF/serum KFLC/albumin and concentrations compared using the Kruskal-Wallis test, Spearman's rank (rs), and Passing-Bablok analysis. Lot-to-lot-variation between three reagent lots was undertaken by analysis of 20 CSF samples.ResultsIntra- and inter-assay imprecision was ≤4.4 and ≤4.1%, respectively. There was a good correlation (rs = ≥0.98) between sites for the measured CSF KFLC concentration, and no significant difference in the median concentration measured between sites (3.31, 2.78, and 3.48 mg/L, <i>P</i> = .98). The median bias between reagent lots was <4%, the intercept of the regression between lots was between -0.02 and 0.06 mg/L, and the slope ranged from 0.96 to 1.07.ConclusionOverall, there was a good agreement in CSF KFLC concentrations among laboratories, and LTLV was deemed acceptable. Ascertaining biological variability of CSF KFLCs and the participation of laboratories in quality assurance schemes would assist with harmonisation.</p>","PeriodicalId":8005,"journal":{"name":"Annals of Clinical Biochemistry","volume":" ","pages":"45632251337616"},"PeriodicalIF":2.1,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143965217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the effect of icterus interference on a creatinine Roche enzymatic methodology.","authors":"Kelsey S Spencer, Louise E Duvall","doi":"10.1177/00045632251337619","DOIUrl":"https://doi.org/10.1177/00045632251337619","url":null,"abstract":"<p><p>BackgroundIt is well established that high bilirubin concentrations can lead to erroneous creatinine results when measured by a Jaffe-based method. However, the effects of bilirubin on enzymatic methods appear less well-defined. The Roche Cobas 8000 enzymatic creatinine (CREP2) has an unconjugated bilirubin icterus limit of 20 mg/dL, equivalent to a bilirubin concentration of 342 µmol/L. Many hepatology patients have bilirubin levels much higher than this limit, and laboratories are unable to release creatinine results on these complex patients. This is particularly challenging for patient management, as creatinine is a key test and is a prerequisite for many procedures, imaging studies and treatments.MethodsTwo spiking studies were carried out, the first to define the interference effect of bilirubin on enzymatic creatinine measurement, and the second to see if this interference could be mitigated via dilution. Serum samples (<i>n</i> = 50) were spiked with a concentrated bilirubin solution. Indices, bilirubin and creatinine were measured using the Roche Cobas 8000 c702 automated analyser according to manufacturer instructions.ResultsThe spiking study found a negative linear relationship and as bilirubin concentrations increased, the measured creatinine concentration decreased (R² = 0.7828, y = -0.0597x + 15.603). Samples with a bilirubin concentration over 246 µmol/L demonstrated an average 1.48% drop in creatinine concentration per 25 µmol/L increase in bilirubin.ConclusionsA service improvement was applied where creatinine results can be released on samples with a bilirubin concentration up to 550 µmol/L, with an appropriate comment, upon request by the clinician.</p>","PeriodicalId":8005,"journal":{"name":"Annals of Clinical Biochemistry","volume":" ","pages":"45632251337619"},"PeriodicalIF":2.1,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143969639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of inadequate drying of blood spots on newborn screening analyte concentrations.","authors":"Stuart J Moat, Melissa Levi, Margaret Birch, Nadia Worlock, Chandra Sundas, Lucy Woodcock, Jude Kay, Sikha de Souza, Annabel Rodham","doi":"10.1177/00045632251337608","DOIUrl":"https://doi.org/10.1177/00045632251337608","url":null,"abstract":"<p><p>BackgroundA critical pre-analytical phase of newborn screening (NBS) testing involves the drying of blood applied to the blood collection devices to form the dried blood spots (DBS). Guidance states that blood applied should be air-dried for a minimum of 3 h. A recent survey highlighted that a number of DBS specimens routinely received into laboratories have a 'crinkled' appearance and that DBS specimens collected in a hospital setting are transported to the laboratory in sealed plastic bags. To date no scientific studies have evaluated aspects of blood drying on DBS NBS analyte concentrations.MethodsWe undertook experiments to recreate 'crinkled' DBS specimens in the laboratory and assess the impact on analyte concentrations. We also assessed the impact of storing collection devices following blood application in hermetically sealed plastic bags to impede the drying process. Experiments were performed using whole blood enriched with thyroid stimulating hormone, immunoreactive trypsinogen, phenylalanine, tyrosine, leucine, methionine, octanoyl-carnitine, decanoyl-carnitine, isovaleryl-carnitine and glutaryl-carnitine to pathophysiological concentrations.Results'Crinkled' DBS specimens produced significantly lower results (mean -15.5%, range -25.1 to -4.7%) for all analytes measured versus air-dried DBS specimens (<i>P</i> < .05). Analyte concentrations obtained from DBS specimens following storage in plastic bags before drying were significantly lower (mean -41.6%, range -60.0 to -27.6%) for all analytes measured (<i>P</i> < .05) versus air-dried DBS specimens.ConclusionResults from this study demonstrate that all DBS specimens with a crinkled appearance and those received in plastic specimen bags should be rejected and a repeat specimen collected to prevent erroneous screening results.</p>","PeriodicalId":8005,"journal":{"name":"Annals of Clinical Biochemistry","volume":" ","pages":"45632251337608"},"PeriodicalIF":2.1,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143962836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thyroid reference ranges in pregnancy utilizing an Abbott Alinity platform in a multi-ethnic population in the UK.","authors":"R V Scott, M Abdel-Malek, J Zhu, J Tan, D Thayabaran, R Valaiyapathi, P Padam, E Jackson, S C Barnes, H Fourie, M Al-Memar, C Kyriacou, M Nimura, T Bourne, N G Martin, R Agha-Jaffar, B Jones, B Khoo, Tm-M Tan","doi":"10.1177/00045632251333286","DOIUrl":"10.1177/00045632251333286","url":null,"abstract":"<p><p>BackgroundMaternal thyroid function significantly affects fetal development. However, thyroid hormone concentrations change dynamically throughout pregnancy rendering non-pregnancy reference ranges inaccurate. We aimed to establish the trimester-, population-, and assay-specific reference ranges for thyroid hormones in pregnancy using the recently introduced Abbott Alinity thyroid function test, according to American Thyroid Association 2017 Guidelines for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum.MethodsThis study of 663, iodine-replete and thyroid peroxidase (TPO)-antibody negative female determined trimester-specific reference ranges for thyroid stimulating hormone (TSH), free thyroxine (fT4), and free tri-iodothyronine (fT3) using Abbott Alinity assays in accordance with ATA guidelines. Study participants were drawn from a multi-ethnic population with 49% non-white participants.ResultsFirst trimester reference ranges were TSH 0.06-2.73 mIU/l, fT4 9.9-15.3 pmol/l, and fT3 3.4-5.6 pmol/l. Second trimester reference ranges were TSH 0.02-2.47 mIU/l, fT4 8.5-14.4 pmol/l, and fT3 3.3-5.5 pmol/l. In the third trimester, TSH ranges were 0.41-2.80 mIU/l, fT4 7.6-12.3 pmol/l, and fT3 3.1-5.0 pmol/l. There were no significant differences in any trimester-specific analyte reference ranges when white and non-white populations were compared.ConclusionsThese reference ranges support the clinical care of female from diverse backgrounds with thyroid dysfunction in pregnancy using the thyroid function tests available on the Abbott Alinity platform.Study registrationISRCTN17018939.</p>","PeriodicalId":8005,"journal":{"name":"Annals of Clinical Biochemistry","volume":" ","pages":"45632251333286"},"PeriodicalIF":2.1,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143741890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of three blood collection tubes for 16 biochemical analytes and stability assessment of selected analytes: VACUETTE^® CAT serum Sep clot activator tube, VACUETTE^® LH lithium heparin Sep tube, and VACUETTE^® CAT serum fast separator tube.","authors":"Jong Do Seo, Yeon Jae Lee, Changhee Ha, Ju Hee Choi, Seon-Hyeon Shin, Hye Young Han, Hyun-Joong Kim, Sung Hea Kim, Bum Sung Kim, Hanah Kim, Hee-Won Moon, Mina Hur, Yeo-Min Yun","doi":"10.1177/00045632251329272","DOIUrl":"https://doi.org/10.1177/00045632251329272","url":null,"abstract":"<p><p>BackgroundAnalytical performance of VACUETTE® CAT Serum Fast Separator Tube (SFT; Greiner Bio-One, Austria), recently developed quick-clotting serum separator, was evaluated for correlation and stability, comparing with VACUETTE® CAT Serum Sep Clot Activator Tube (SST; Greiner Bio-One) and VACUETTE® LH Lithium Heparin Sep Tube (LiHep Tube; Greiner Bio-One).MethodFor 107 paired samples, 16 analytes (glucose, potassium, LDH, CRP, creatinine, AST, ALT, ALP, GGT, AFP, PSA, TSH, free T4, iPTH, CK-MB, and cardiac troponin I[cTnI]) were measured. Correlations were assessed using Passing-Bablok regression and paired t-tests. Differences were evaluated by comparing the mean percentage difference and estimated difference at medical decision limits (MDLs), to the acceptable desirable difference. For six analytes - glucose, potassium, LDH, AST, iPTH, and cTnI - known for different stabilities between sample types, stability was evaluated by comparing changes over time with desirable differences.ResultsAcross the evaluated range, SFT showed clinically comparable differences to SST, except for CK-MB which showed significant positive bias. Plasma exhibited unacceptable biases: negative for potassium and positive for LDH and CK-MB. Estimated differences at MDLs were acceptable in SFT except for potassium and CK-MB, while plasma showed unacceptable differences in potassium, LDH, creatinine, and CK-MB. LiHep Tube showed reduced stability than SST for all analytes except for iPTH, impairing retest reliability. SFT showed comparable stability except for LDH and iPTH, which showed slightly shortened stability.ConclusionsThe SFT demonstrated high correlation and comparable stability to SST, making it a suitable replacement for the LiHep Tube, as an alternative to SST for rapid testing.</p>","PeriodicalId":8005,"journal":{"name":"Annals of Clinical Biochemistry","volume":" ","pages":"45632251329272"},"PeriodicalIF":2.1,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143707897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Underreporting of synthetic cathinone poisoning with clinical immunoassays: An experimental and observational study.","authors":"Théo Willeman, Mathis Laudet, Bruno Revol, Coralie Boudin, Hélène Eysseric-Guerin, Virginie Scolan, Françoise Stanke-Labesque","doi":"10.1177/00045632251331404","DOIUrl":"10.1177/00045632251331404","url":null,"abstract":"<p><p>BackgroundThere is an increasing global concern about the use of synthetic cathinones (SCs). Detecting these drugs in human urine samples can be difficult, particularly in emergency settings. Cross-reactivity has been described for several immunoassays. We evaluated the analytical interference caused by common SCs in MDMA and amphetamine assays that use the EMIT® Atellica CH (Siemens Healthineers) with both clinical and in vitro experimental data.MethodsDrug-free urine samples were spiked with various concentrations (5 to 100 µg/mL) of 2-methylmethcathinone (MMC), 3-MMC, 4-MMC, 3-chloromethcathinone (CMC), methylone and alpha-PHP and tested using EMIT® assays. The percentage of false-positive results was determined in urine samples from patients above 18 years of age admitted to the ICU or emergency department who underwent routine toxicology screening and urine immunoassays over a 4-year period. Confirmatory analyses of SC were performed by mass spectrometry techniques.ResultsFalse-positive results occurred for the MDMA assay with methylone (10 µg/mL) and 3-CMC (100 µg/mL) and for the amphetamine test with 2-MMC (50 µg/mL). We studied 2033 urine samples from 1812 patients (mean age 39 years, 61.8% male), of which 49 tested positive for amphetamine and 76 for MDMA. SCs were responsible for a false-positive rate of 16.3% for the amphetamine tests and 17.1% for the MDMA tests. Most of the false-positive tests occurred among young male patients (mean age 38 years, 92.8% male).ConclusionsThis study demonstrates that SC intoxication may be underreported in immunoassay toxicology testing. Due to a lack of specificity of screening immunoassay methods, positive results for amphetamine-type stimulants should be confirmed by specific MS methods.</p>","PeriodicalId":8005,"journal":{"name":"Annals of Clinical Biochemistry","volume":" ","pages":"45632251331404"},"PeriodicalIF":2.1,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143673195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A five-year retrospective analysis of a national external quality assessment program for urinary organic acid analysis in newborn screening for inherited metabolic disorders in China.","authors":"Yuxuan Du, Wei Wang, Yanling Yang, Zhiguo Wang","doi":"10.1177/00045632251332460","DOIUrl":"10.1177/00045632251332460","url":null,"abstract":"<p><p>ObjectivesUrinary organic acid analysis is crucial for diagnosing inherited metabolic disorders (IMDs). This study assesses the impact of an external quality assessment (EQA) scheme on standardizing urinary organic acid detection in China from 2019 to 2023.MethodsThis retrospective longitudinal study analysed data from the NCCL-E-25 EQA scheme for urinary organic acid analysis using gas chromatography-mass spectrometry (GC-MS). Ten batches of EQA data over 5 years were included, focussing on eight key organic acid metabolites. Robust statistical methods were used to evaluate laboratory performance, including regional variations, sample preparation methods, and laboratory types.ResultsParticipating laboratories increased from 43 in 2019 to 76 in 2023, with high participation rates (median 94.74%). All eight target compounds showed significant reductions in robust coefficient of variation (CV) over time. Regional performance disparities narrowed, converging by 2022-2023. Extraction preparation methods generally outperformed non-extraction methods. Newborn Screening Centers (NBSCs) demonstrated lower robust CVs compared to non-NBSCs.ConclusionsThe EQA scheme effectively improved and standardized laboratory testing quality nationwide, particularly benefiting central and western regions. The study highlights the importance of standardized protocols and continuous improvement in enhancing IMD diagnostic accuracy. Future efforts should focus on encouraging wider participation, especially from underrepresented regions, and integrating quantitative and diagnostic capability assessments to comprehensively evaluate laboratory performance.</p>","PeriodicalId":8005,"journal":{"name":"Annals of Clinical Biochemistry","volume":" ","pages":"45632251332460"},"PeriodicalIF":2.1,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143673194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Decrease in the internal quality control intermediate reproducibility imprecision of Cystatin C results in China in the years from 2014 to 2023.","authors":"Zhixin Zhang, Jie Zeng, Wei Wang, Yuxuan Du, Shuai Yuan, Na Dong, Chuanbao Zhang, Zhiguo Wang","doi":"10.1177/00045632251329182","DOIUrl":"10.1177/00045632251329182","url":null,"abstract":"<p><p>ObjectivesWe evaluated the intermediate reproducibility imprecision of cystatin C results based on internal quality control (IQC) data.MethodsIQC data for cystatin C analyte were collected each year from 2014 to 2023. We used the coefficient of variation (CV) to evaluate the level of laboratory imprecision. Five performance specifications [1/3 total allowable error (TEa), 1/4TEa and three levels performance specifications based on biological variation] were used to calculate the proportion of laboratories with CVs less than or equal to the performance specifications, namely, the pass rate. Based on the reference interval of Chinese adult serum cystatin C (0.59-1.03 mg/L), the concentration of quality control materials was divided into two levels for CV analysis: Level 1 (≤1.03 mg/L) and Level 2 (>1.03 mg/L). Additionally, group analysis was conducted according to the reagent manufacturer. Peer groups were further divided based on instruments to study differences between instruments. Boxplots were drawn to analyze trends in CVs, and differences in CVs among different groups were assessed using the Kruskal-Wallis test and Mann-Whitney U test.ResultsThe number of participating laboratories increased significantly from 255 in 2014 to 1814 in 2023. The intermediate reproducibility imprecision of Cystatin C IQC results in China had decreased from 5.1% (CV%) in 2014 to 3.3% in 2023. The pass rates based on 1/3 TEa showed upward trends increasing from 67% in 2014 to 88% in 2023. The pass rates for the other four performance specifications were all below 80%. The CVs of two concentration levels showed significant differences in most years. Roche Diagnostics reagent manufacturer exhibited low intermediate reproducibility imprecision. The BSBE-Abbott Architect series platform achieved a 100% pass rate based on 1/3 TEa in 2023.ConclusionsThe intermediate reproducibility imprecision of cystatin C has been a continuous overall improvement in China. However, the performance specifications of Cystatin C based on BV are currently not applicable to some laboratories in China. In addition, attention should be paid to the differences in intermediate reproducibility imprecision between various analysis systems.</p>","PeriodicalId":8005,"journal":{"name":"Annals of Clinical Biochemistry","volume":" ","pages":"45632251329182"},"PeriodicalIF":2.1,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143630069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}