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BACKGROUND: In clinical laboratories, the precision and sensitivity of autoverification technologies are crucial for ensuring reliable diagnostics. Conventional methods have limited sensitivity and applicability, making error detection challenging and reducing laboratory efficiency. This study introduces a machine learning (ML)-based autoverification technology to enhance tumor marker test error detection. METHODS: The effectiveness of various ML models was evaluated by analyzing a large data set of 397 751 for model training and internal validation and 215 339 for external validation. Sample misidentification was simulated by random shuffling error-free test results with a 1% error rate to achieve a real-world approximation. The ML models were developed with Bayesian optimization for tuning. Model validation was performed internally at the primary institution and externally at other institutions, comparing the ML models' performance with conventional delta check methods. RESULTS: Deep neural networks and extreme gradient boosting achieved an area under the receiver operating characteristic curve of 0.834 to 0.903, outperforming that of conventional methods (0.705 to 0.816). External validation by 3 independent laboratories showed that the balanced accuracy of the ML model ranged from 0.760 to 0.836, outperforming the balanced accuracy of 0.670 to 0.773 of the conventional models. CONCLUSIONS: This study addresses limitations regarding the sensitivity of current delta check methods for detection of sample misidentification errors and provides versatile models that mitigate the operational challenges faced by smaller laboratories. Our findings offer a pathway toward more efficient and reliable clinical laboratory testing.
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OBJECTIVES: To evaluate the performance of the Academia-Government Collaboration for Laboratory Medicine Standardization in Korea (KR-STDZN) based on data from KR-STDZN proficiency testing (KR-STDZN-PT) for creatinine over eight years (2015-2022). METHODS: We used KR-STDZN-PT data of creatinine tests from 2015 to 2022. Acceptance of the participating institutions' test results was assessed by calculating the acceptance performance as absolute bias (absBias%), total coefficient of variance (tCV%), and total error (TE%) for each sample using six measurements from each institution and true values of each reference material. The test result was considered acceptable when absBias%, tCV%, and TE% were <5.10, <3.20, and <11.40â¯%, respectively. The proportion of acceptable institutions among all participating institutions in each round was defined as the acceptance rate. Improvements in absBias%, tCV%, and TE% were analyzed using creatinine concentration ranges in samples. RESULTS: The number of participating institutions increased from 2015 to 2017 but remained consistent since 2018. The acceptance rates for absBias% and TE% increased from 52.2 and 77.6â¯%, in 2015 and to 90.7 and 96.3â¯%, in 2022, respectively. The acceptance rate for tCV% remained in the 90â¯% range for eight years. When creatinine <3â¯mg/dL, mean absBias%, and mean TE% improved significantly in 2021-2022 compared to 2015-2016 (p<0.05). When creatinine >3â¯mg/dL, acceptance performance did not improve. Mean tCV% remained consistent annually regardless of creatinine concentration. No significant variations in test methods were observed. CONCLUSIONS: The collaboration between academia and the government improved creatinine testing quality. Nevertheless, KR-STDZN must be expanded and refined.
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Academia , Ensaio de Proficiência Laboratorial , Humanos , Creatinina , Padrões de Referência , GovernoRESUMO
BACKGROUND: This study investigated the performance evaluation of total prostate specific antigen (tPSA) testing using Cobas Pure integrated solutions system (calibrated against WHO IS 96/670) and the comparison with established measurement systems with different traceability. METHODS: The evaluation was performed in terms of imprecision, linearity, detection limit, and correlation with Alinity i (calibrated against WHO IS 96/670) and Unicel DxI 800 (calibrated against the manufacturer's working calibrators). RESULTS: Within-laboratory reproducibility and repeatability were observed less than 1.2%. Linearity was achieved within the claimed analytical measurement range. The claimed LoB and LoD were experimentally verified. All the correlation coefficients among the assays indicated good correlation, but the significant mean bias with Unicel DxI 800 using a different calibrator were observed. CONCLUSIONS: Since the tPSA calibrators against different traceability is still commercially available, our research could convey the impact of calibration on tPSA results as well as the performance information of a new assay for tPSA.
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Antígeno Prostático Específico , Neoplasias da Próstata , Humanos , Masculino , Calibragem , Reprodutibilidade dos Testes , Testes Imunológicos , Laboratórios , Neoplasias da Próstata/diagnósticoRESUMO
BACKGROUND: Small dense low-density lipoprotein (sdLDL) possesses atherogenic potential and is predicted to be susceptible to atherogenic modifications, which further increases its atherogenicity. However, studies on the association between measured or estimated sdLDL cholesterol (sdLDL-C) levels and atherogenic modification in diverse population groups are lacking. METHODS: Surplus serum samples were collected from male subjects with type 2 diabetes mellitus (DM) under treatment (n = 300) and without DM (non-DM; n = 150). sdLDL and oxidized LDL (oxLDL) levels were measured using the Lipoprint LDL subfractions kit (Quantimetrix Corporation) and the Mercodia oxidized LDL competitive enzyme-linked immunosorbent assay kit (Mercodia), respectively. The estimated sdLDL-Cs were calculated from two relevant equations. The effects of sdLDL-C on oxLDL were assessed using multiple linear regression (MLR) models. RESULTS: The mean (±SD) of measured sdLDL-C and oxLDL concentrations were 11.8 ± 10.0 mg/dl and 53.4 ± 14.2 U/L in the non-DM group and 0.20 ± 0.81 mg/dl and 46.0 ± 15.3 U/L in the DM group, respectively. The effects of measured sdLDL-Cs were significant (p = 0.031), whereas those of estimated sdLDL-Cs were not (p = 0.060, p = 0.116) in the non-DM group in the MLR models. The effects of sdLDL-Cs in the DM group were not significant. CONCLUSION: In the general population, high level of sdLDL-C appeared to be associated with high level of oxLDL. The equation for estimating sdLDL-C developed from a general population should be applied with caution to a special population, such as patients with DM on treatment.
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Aterosclerose , Diabetes Mellitus Tipo 2 , Humanos , Masculino , LDL-Colesterol , Biomarcadores , Fatores de RiscoRESUMO
BACKGROUND: Turnaround 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. METHODS: As 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. RESULTS: The 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). CONCLUSIONS: We 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.
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Laboratórios Hospitalares , Pacientes Ambulatoriais , Humanos , Manejo de Espécimes , Fatores de TempoRESUMO
BACKGROUND: Automated microscopic platforms are increasingly used in clinical laboratories for rapid analysis of samples. However, it is important to present the results quantitatively or semiquantitatively because automated platforms use various technologies for analysis as well as different sediment preparation methods. The results of cell counting using an on screen image review program for the cobas u 701 analyzer (Roche Diagnostics Interna-tional, Rotkreuz, Switzerland) differed from those obtained by manual microscopic examination (MME). This study was performed to investigate the difference of results among analyzer, on-screen image review and MME. METHODS: Freshly collected urine specimens from outpatients were used. We calculated the mean, standard deviation, and 95% confidence interval for red and white blood cell (RBC/WBC) quantitative results obtained using the cobas u 701 analyzer. These results were compared to those obtained by manual counting. RBC and WBC counts determined with the cobas u 701 analyzer were compared to those obtained by MME per unit field. RESULTS: The semiquantitative results of MME were graded as 0 - 2, 3 - 5, 6 - 10, 11 - 20, 21 - 30, and many or numerous cells/high power field (HPF). The RBC and WBC counts determined by image analyses showed the tendency to be one grade higher than those from MME in the range of 3 to 5/HPF to many/HPF. The results of nearly all samples with 0 - 2/HPF and numerous/HPF for RBC and WBC counts were consistent with the grade found by MME. CONCLUSIONS: The one-grade difference may have been caused by the differences of preanalytical factors in the sample volume, centrifugal force, urine concentration ratio, or sediment volume/area of the slide. When reporting the results of image analyses, RBC and WBC counts should be raised by one grade to compensate for MME. Each laboratory needs to verify the on-screen review of images corresponding to the microscopic field of view according to the clinical laboratory's specific preanalytical practices.
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Microscopia , Urinálise , Laboratórios , Contagem de Leucócitos , Leucócitos , UrinaRESUMO
BACKGROUND: Essential trace elements play key roles in multiple biological systems, and hemodialysis patients are at risk for deficiency of essential trace elements. The aim of the study was to assess the essential element status in end stage renal disease patients undergoing online hemodiafiltration (online HDF) in outpatient dialysis clinic. METHODS: A total of 28 Korean patients with regular online HDF were included. Blood samples were collected before and after one HDF session, and serum concentrations of zinc, copper, selenium, and manganese were simulta-neously measured by inductively coupled plasma mass spectrometry. RESULTS: Selenium, zinc, copper deficiencies were observed in 71.4%, 35.8%, and 21.4%, compared with the reference range. No patients revealed manganese deficiency. After the HDF, the post-HDF level significantly increased in all trace elements, compared with the pre-HDF (11.2% for selenium, 10.7% for copper, and 6.6% for zinc). However, 50% patients were still deficient for selenium at the post-HDF. CONCLUSIONS: Our data suggest that the patients undergoing online HDF are at an increased risk of trace element deficiency, especially for selenium.
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Hemodiafiltração , Selênio , Oligoelementos , Idoso , Cobre , Humanos , ZincoRESUMO
External quality assessment (EQA) is essential for ensuring reliable test results, especially when laboratories are using assays authorized for emergency use for newly emerging pathogens. We developed an EQA panel to assess the quality of real-time reverse transcription PCR assays being used in South Korea to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). With the participation of 23 public health organization laboratories and 95 nongovernmental laboratories involved in SARS-CoV-2 testing, we conducted qualitative and semiquantitative performance assessments by using pooled respiratory samples containing different viral loads of SARS-CoV-2 or human coronavirus OC43. A total of 110 (93.2%) laboratories reported correct results for all qualitative tests; 29 (24.6%) laboratories had >1 outliers according to cycle threshold values. Our EQA panel identified the potential weaknesses of currently available commercial reagent kits. The methodology we used can provide practical experience for those planning to conduct evaluations for testing of SARS-CoV-2 and other emerging pathogens in the future.
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Betacoronavirus/isolamento & purificação , Técnicas de Laboratório Clínico/normas , Infecções por Coronavirus/diagnóstico , Pneumonia Viral/diagnóstico , RNA Viral/análise , Reação em Cadeia da Polimerase em Tempo Real/normas , Reação em Cadeia da Polimerase Via Transcriptase Reversa/normas , COVID-19 , Teste para COVID-19 , Vacinas contra COVID-19 , Humanos , Ensaio de Proficiência Laboratorial , Pandemias , Garantia da Qualidade dos Cuidados de Saúde , Kit de Reagentes para Diagnóstico/normas , Reação em Cadeia da Polimerase em Tempo Real/métodos , República da Coreia , Sistema Respiratório/virologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , SARS-CoV-2RESUMO
The clinical utility of BRCA1/2 genotyping was recently extended from the selection of subjects at high risk for hereditary breast and ovary cancer to the identification of candidates for poly (ADP-ribose) polymerase (PARP) inhibitor treatment. This underscores the importance of accurate interpretation of BRCA1/2 genetic variants and of reducing the number of variants of uncertain significance (VUSs). Two recent studies by Findlay et al. and Starita et al. introduced high-throughput functional assays, and proactively analyzed variants in specific regions regardless of whether they had been previously observed. We retrospectively reviewed all BRCA1 and BRCA2 germline genetic test reports from patients with breast or ovarian cancer examined at Asan Medical Center (Seoul, Korea) between September 2011 and December 2018. Variants were assigned pathogenic or benign strong evidence codes according to the functional classification and were reclassified according to the ACMG/AMP 2015 guidelines. Among 3684 patients with available BRCA1 and BRCA2 germline genetic test reports, 429 unique variants (181 from BRCA1) were identified. Of 34 BRCA1 variants intersecting with the data reported by Findlay et al., three missense single-nucleotide variants from four patients (0.11%, 4/3684) were reclassified from VUSs to likely pathogenic variants. Four variants scored as functional were reclassified into benign or likely benign variants. Three variants that overlapped with the data reported by Starita et al. could not be reclassified. In conclusion, proactive high-throughput functional study data are useful for the reclassification of clinically observed VUSs. Integrating additional evidence, including functional assay results, may help reduce the number of VUSs.
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Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/genética , Neoplasias Ovarianas/genética , Adulto , Idoso , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/patologia , Feminino , Predisposição Genética para Doença , Testes Genéticos , Variação Genética/genética , Genótipo , Mutação em Linhagem Germinativa/genética , Humanos , Pessoa de Meia-Idade , Mutação de Sentido Incorreto/genética , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/epidemiologia , Neoplasias Ovarianas/patologia , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Poli(ADP-Ribose) Polimerases/genética , República da Coreia/epidemiologiaRESUMO
We aimed to determine the surveillance performance of alpha-fetoprotein (AFP), lectin-reactive AFP (AFP-L3), des-gamma-carboxy prothrombin (DCP), and their combinations for the early detection of hepatocellular carcinoma (HCC) by using prospectively collected longitudinal samples in patients at risk. Among 689 patients with cirrhosis and/or chronic hepatitis B who participated in four prospective studies, 42 HCC cases were diagnosed, selected, and matched with 168 controls for age, sex, etiology, cirrhosis, and duration of follow-up in a 1:4 ratio. Levels of AFP, AFP-L3, and DCP at the time of HCC diagnosis, month -6, and month -12 were compared between cases and controls. Of 42 HCC cases, 39 (93%) had cirrhosis, 36 (85.7%) had normal alanine aminotransferase levels, and 31 (73.8%) had very early-stage HCC (single <2 cm). AFP and AFP-L3 began to increase from 6 months before diagnosis of HCC in cases (P < 0.05), while they remained unchanged in controls. At HCC diagnosis, the area under the receiver operator characteristic curves (AUROCs) for AFP, AFP-L3, and DCP were 0.77, 0.73, and 0.71, respectively. Combining AFP and AFP-L3 showed a higher AUROC (0.83), while adding DCP did not further improve the AUROC (0.86). With the optimal cutoff values (AFP, 5 ng/mL; AFP-L3, 4%), the sensitivity and specificity of AFP and AFP-L3 combination were 79% and 87%, respectively. The sensitivity of ultrasonography was 48.6%, which was increased to 88.6% and 94.3% by adding AFP and AFP + AFP-L3, respectively. Conclusion: Among three biomarkers, AFP showed the best performance in discriminating HCC cases from controls; the AFP and AFP-L3 combination, adopting cutoff values (5 ng/mL and 4%, respectively), significantly improved the sensitivity for detecting HCC at a very early stage.
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Biomarcadores/sangue , Carcinoma Hepatocelular/sangue , Neoplasias Hepáticas/sangue , Precursores de Proteínas/sangue , alfa-Fetoproteínas/metabolismo , Idoso , Carcinoma Hepatocelular/diagnóstico , Estudos de Casos e Controles , Diagnóstico Precoce , Feminino , Humanos , Neoplasias Hepáticas/diagnóstico , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , ProtrombinaRESUMO
BACKGROUND: Genetic variants may play a role in determining the location of cerebral atherosclerosis. We aimed to investigate the association between RNF213, MMP2, and genetic polymorphisms linked to vascular tortuosity with the location of cerebral arterial atherosclerosis. METHODS: A prospective case-control study was conducted on patients with ischemic stroke and age- and sex-matched stroke-free controls. The stroke patients were categorized into those with intracranial artery atherosclerosis (ICAS), extracranial artery atherosclerosis (ECAS), and small vessel occlusion (SVO). Six single nucleotide polymorphisms (SNPs) including rs2118181 (FBN1), rs2179357 (SLC2A10), rs1036095 (TGFBR2), rs243865 (MMP2), rs1800470 (TGFB1), and rs112735431 (RNF213) were analyzed with the TaqMan Genotyping Assay, and the distribution of genotypes across groups was compared. RESULTS: None of the 6 SNPs were associated with stroke on comparing the 449 stroke patients (71 with ECAS, 169 with ICAS, and 209 with SVO) to the 447 controls. In the subgroup analysis, the adjusted odds ratios (aORs) for age and sex indicated a significant association between rs112735431 and ICAS in the allele comparison analysis and in the additive and dominant model analyses. rs112735431 was associated with anterior circulation involvement and increased burden of cerebral atherosclerosis. rs2179357 was significantly associated with ICAS in the recessive model analysis, and rs1800470 was significantly associated with ECAS in the recessive model analysis when compared to controls. CONCLUSION: rs112735431 was associated with ICAS and increased atherosclerosis burden in Korean stroke patients. Further studies are needed to elucidate the role of rs112735431 and to confirm the association of rs2179357 and rs1800470 with cerebral atherosclerosis.
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Adenosina Trifosfatases/genética , Doenças de Pequenos Vasos Cerebrais/genética , Arteriosclerose Intracraniana/genética , Polimorfismo de Nucleotídeo Único , Acidente Vascular Cerebral/genética , Ubiquitina-Proteína Ligases/genética , Idoso , Estudos de Casos e Controles , Doenças de Pequenos Vasos Cerebrais/diagnóstico por imagem , Feminino , Fibrilina-1/genética , Predisposição Genética para Doença , Proteínas Facilitadoras de Transporte de Glucose/genética , Humanos , Arteriosclerose Intracraniana/diagnóstico por imagem , Masculino , Metaloproteinase 2 da Matriz/genética , Pessoa de Meia-Idade , Fenótipo , Receptor do Fator de Crescimento Transformador beta Tipo II/genética , Medição de Risco , Fatores de Risco , Seul , Acidente Vascular Cerebral/diagnóstico por imagem , Fator de Crescimento Transformador beta1/genéticaRESUMO
BACKGROUND: Delta check is a patient-based QC tool for detecting errors by comparing current and previous test results of patient. Reference change value (RCV) is adopted in guidelines as method for delta check, but the performance is not verified. We applied RCV-based delta check method to patients' data and modified for application. MATERIALS AND METHODS: Reference change value were calculated using results of internal QC materials and biological variation data. Test results of 17 analytes in inpatients, outpatients, and health examination recipients were collected. The detection rates of currently used delta check method and those of RCV-based method were compared, and the methods were modified. RESULTS: Reference change value-based method had higher detection rates compared to conventional method. Applied modifications reduced detection rates. Removing the pairs of results within reference interval reduced detection rates (0.42% ~ 10.92%). When RCV was divided by time interval, the detection rates were similar to prior rates in outpatients (0.19% ~ 1.34%). Using RCV multiplied by twice the upper limit of reference value as cutoff reduced the detection rate (0.07% ~ 1.58%). CONCLUSIONS: Reference change value is a robust criterion for delta check and included in clinical laboratory practice guideline. However, RCV-based method generates high detection rates which increase workload. It needs modification for use in clinical laboratories.
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Testes de Química Clínica/normas , Melhoria de Qualidade , Testes de Química Clínica/métodos , Humanos , Valores de Referência , Reprodutibilidade dos TestesRESUMO
BACKGROUND: As next-generation sequencing (NGS) technology matures, various amplicon-based NGS tests for BRCA1/2 genotyping have been introduced. This study was designed to evaluate an NGS test using a newly released amplicon-based panel, AmpliSeq for Illumina BRCA Panel (AmpliSeq panel), for detection of clinically significant BRCA variants, and to compare it to another amplicon-based NGS test confirmed by Sanger sequencing. METHODS: We reviewed BRCA test results done by NGS using the TruSeq Custom Amplicon kit from patients suspected of hereditary breast/ovarian cancer syndrome (HBOC) in 2018. Of those, 96 residual samples with 100 clinically significant variants were included in this study using predefined criteria: 100 variants were distributed throughout the BRCA1 and BRCA2 genes. All target variants were confirmed by Sanger sequencing. Duplicate NGS testing of these samples was performed using the AmpliSeq panel, and the concordance of results from the two amplicon-based NGS tests was assessed. RESULTS: Ninety-nine of 100 variants were detected in duplicate BRCA1/2 genotyping using the AmpliSeq panel (sensitivity, 99%; specificity, 100%). In the discordant case, one variant (BRCA1 c.3627dupA) was found only in repeat 1, but not in repeat 2. Automated nomenclature of all variants, except for two indel variants, was in consensus with Human Genome Variation Society nomenclature. CONCLUSION: Our findings confirm that the analytic performance of the AmpliSeq panel is satisfactory, with high sensitivity and specificity.
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Proteína BRCA1/genética , Proteína BRCA2/genética , Sequenciamento de Nucleotídeos em Larga Escala , Análise de Sequência de DNA , Feminino , Variação Genética/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Sequenciamento de Nucleotídeos em Larga Escala/normas , Humanos , Sensibilidade e Especificidade , Análise de Sequência de DNA/métodos , Análise de Sequência de DNA/normasRESUMO
BACKGROUND: We evaluated the analytical performance of a newly developed electrochemiluminescence immunoassay for everolimus and sirolimus compared to that of liquid chromatography-tandem mass spectrometry (LC-MS/MS). METHODS: According to Clinical and Laboratory Standards Institute guidelines, the analytical performance including precision, recovery, linearity, and carryover was evaluated. For correlation evaluation, the results of Elecsys® analysis of everolimus and sirolimus were compared with those of LC-MS/MS using 120 samples from patients treated with everolimus or sirolimus. RESULTS: The within-run and total imprecision values were as follows: 2.3%-4.5% and 4.5%-6.4% for the everolimus assay; 3.3%-4.8% and 4.7%-8.1% for the sirolimus assay, respectively. The measured concentration was linear over the range of 0.718-27.585 ng/mL for everolimus analysis and 0.789-26.880 ng/mL for sirolimus analysis (all R2 > 0.99). Recovery was 93.5%-105.5% for the everolimus assay and 99.2%-109.1% for the sirolimus assay (except lowest levels). Carryover was -1.09% for the everolimus assay and -0.12% for the sirolimus assay. The results of the two chemiluminescence immunoassays showed acceptable correlations with those of LC-MS/MS (R = 0.9585 and R = 0.9799, respectively). The two immunoassays showed slightly proportional biases compared to LC-MS/MS. CONCLUSION: Elecsys® Everolimus and Sirolimus assays showed acceptable analytical performance in precision, linearity, and correlation compared to LC-MS/MS These methods can be adopted in the clinical laboratory for rapid therapeutic drug monitoring of patients who require treatment with immunosuppressants.
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Cromatografia Líquida/métodos , Everolimo/análise , Imunoensaio/métodos , Medições Luminescentes/métodos , Sirolimo/análise , Espectrometria de Massas em Tandem/métodos , Automação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise de RegressãoRESUMO
Therapeutic drug monitoring of tacrolimus and cyclosporine is crucial to the success of organ transplantation. We evaluated the analytical performances and accuracy of two commercially available tacrolimus and cyclosporine assays (Roche ISD and Siemens) in comparison with liquid chromatography-tandem mass spectrometry (LC-MS/MS). A total of 342 leftover whole blood samples requested for tacrolimus or cyclosporine assays were stored at -20 °C until analysis. Repeatability and between-run imprecision were evaluated using quality control materials provided by the manufacturer. Ring trial samples were used for the assessment of recovery. The results of the Roche ISD assay were compared with those of Siemens tacrolimus and cyclosporine assays and LC-MS/MS. Repeatability and between-run imprecision were 2.1-5.3% and 2.6-7.5%, respectively. Recovery of Roche ISD was 85.7 - 90.6% for cyclosporine and 96.2-98.5% for tacrolimus. The two immunoassays showed slight positive biases relative to LC-MS/MS for cyclosporine. For tacrolimus, Roche ISD produced virtually identical results to those of LC-MS/MS, whereas Siemens showed proportional differences, especially in patients receiving kidney transplantation. The analytical performances of Roche ISD were generally acceptable, especially regarding accuracy. Clinical laboratory staff should be aware of the strengths and weaknesses of commercial immunoassays in order to ensure accurate results.
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Ciclosporina/sangue , Monitoramento de Medicamentos/métodos , Imunoensaio/normas , Imunossupressores/sangue , Tacrolimo/sangue , Cromatografia Líquida/normas , Transplante de Coração , Humanos , Transplante de Rim , Transplante de Fígado , Variações Dependentes do Observador , Controle de Qualidade , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem/normasRESUMO
BACKGROUND: Therapeutic monitoring of tacrolimus is essential for reducing organ rejection and adverse effects. The measurement of tacrolimus in whole blood is taken by many automated platforms. We evaluated the analytical performance of the Dimension TAC assay, which is an upgraded reagent from the previous Dimension TACR assay. METHODS: The evaluations involved determination of precision, linearity, detection capability, and reagent lot-to-lot variability between three lot numbers. Correlation studies were conducted using the Dimension TACR assay, Architect, Elecsys assay, and MassTrak LC-MS/MS. RESULTS: The total coefficient of variation was below 10%. Acceptable linearity was observed in their respective reportable ranges. The limit of blank, limit of detection, and limit of quantification were 0.29, 0.47, and 0.81 ng/mL, respectively. Correlation analysis indicated that the Dimension TAC assay results were comparable to that of the Dimension TACR assay, Architect, and Elecsys results in liver and heart transplant patients. In kidney transplant patients, the Dimension TAC assay showed the poor correlation with Architect and Elecsys. The results from these assays were slightly higher than that of MassTrak. We found little lot-to-lot reagent variation among the reagents evaluated. CONCLUSION: The overall analytical performance of the Dimension TAC assay is acceptable for therapeutic monitoring in clinical practice. Our study that compared different platforms may provide some useful information regarding which test method to use.
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Monitoramento de Medicamentos/métodos , Imunossupressores/sangue , Tacrolimo/sangue , Transplante de Coração , Humanos , Limite de Detecção , Modelos Lineares , Transplante de Fígado , Reprodutibilidade dos TestesRESUMO
BACKGROUND: The updated bedside Schwartz equation requires constant, serum creatinine concentration and height measurements to calculate the estimated glomerular filtration rate (eGFR) in pediatric patients. Unlike the serum creatinine levels, obtaining height information from the laboratory information system (LIS) is not always possible in a clinical laboratory. Recently, the height-independent eGFR equation, the full age spectrum (FAS) equation, has been introduced. We evaluated the performance of height-independent eGFR equation in Korean children with cancer. METHODS: A total of 250 children who underwent chromium-51-ethylenediamine tetra acetic-acid (51Cr-EDTA)-based glomerular filtration rate (GFR) measurements were enrolled. The 51Cr-EDTA GFR was used as the reference GFR. The bias (eGFR - measured GFR), precision (root mean square error [RMSE]) and accuracy (P30) of the FAS equations were compared to those of the updated Schwartz equation. P30 was defined as the percentage of patients whose eGFR was within ±30% of the measured GFR. RESULTS: The FAS equation showed significantly lower bias (mL/min/1.73 m2) than the updated Schwartz equation (4.2 vs. 8.7, p<0.001). The RMSE and P30 were: updated Schwartz of 43.8 and 64.4%, respectively, and FAS of 42.7 and 66.8%, respectively. CONCLUSIONS: The height-independent eGFR-FAS equation was less biased and as accurate as the updated Schwartz equation in Korean children. The use of the height-independent eGFR equation will allow for efficient reporting of eGFR through the LIS in clinical laboratories.
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Taxa de Filtração Glomerular , Neoplasias/diagnóstico , Adolescente , Estatura , Criança , Pré-Escolar , Creatinina/sangue , Feminino , Humanos , Masculino , Neoplasias/sangue , Estudos RetrospectivosRESUMO
BACKGROUND: Reliable quantitative measurements of HE4 and CA125 levels are required to calculate the risk of ovarian malignancy algorithm (ROMA) value. We suggest a new reporting strategy for interpreting ROMA values based on analytical measurement range (AMR) and qualified-intervals of the HE4 and CA125 results. METHODS: HE4 and CA125 assays from Abbott and Roche were used. The AMRs and the qualified-intervals were as follows: Architect HE4 assay, 20-1500 and 17.2-2637.8 pmol/L; Architect CA125 II assay, 1-1000 and 3.9-14,163.0 U/mL; Elecsys HE4 assay, 15-1500 and 28.8-3847 pmol/L; Elecsys CA125 II assay, 0.6-5000 and 6.5-5000 U/mL. These values were used to simulate the ROMA values. RESULTS: Reporting algorithm for the ROMA value could be classified into three categories. (1) If quantitative HE4 and CA125 levels are reliable, the numerical ROMA value can be reported. (2) If HE4 value is <20 and <28.8 for Abbott and Roche in premenopausal woman, the ROMA value should be reported as "low risk" regardless of the CA125 result. In postmenopausal woman, however, it should be reported as "low risk" (CA125<203.0 and <165.8 for Abbott and Roche) or "undetermined" (vice-versa value). (3) If CA125 value is <3.9 and <6.5 for Abbott and Roche, it should be reported as "low risk" (premenopausal HE4<51.5 and <62.2, postmenopausal HE4<323.0 and <281.5 for Abbott and Roche) or "undetermined" (vice-versa value). CONCLUSIONS: New reporting strategy will provide more informative reporting of ROMA values in clinical practice.
Assuntos
Algoritmos , Biologia Computacional/métodos , Medição de Risco/métodos , Antígeno Ca-125/sangue , Feminino , Humanos , Proteínas de Membrana/sangue , Neoplasias Ovarianas , Pós-Menopausa/sangue , Pré-Menopausa/sangue , Proteínas/análise , Proteína 2 do Domínio Central WAP de Quatro DissulfetosRESUMO
BACKGROUND: Quantification of glycated hemoglobin (HbA1c) is a challenge in patients with hemoglobin (Hb) variants. We evaluated the impact of various Hb variants on five routine HbA1c assays by comparing with the IFCC reference measurement procedure (RMP). METHODS: Whole blood samples showing warning flags or no results on routine HPLC HbA1c assays were confirmed for Hb variants and were submitted to HbA1c quantification using Sebia Capillarys 2 Flex Piercing, Roche Tina-quant HbA1c Gen. 2, Bio-Rad Variant II Turbo 2.0, ADAMS HA-8180, Tosoh G8 standard mode, and IFCC RMP using LC-MS. RESULTS: Among 114 samples, the most common variants were Hb G-Coushatta (n=47), Queens (n=41), Ube-4 (n=11), Chad (n=4), Yamagata (n=4), G-His-Tsou (n=2), G-Taipei (n=1), Fort de France (n=1), Hoshida (n=1), and two novel variants (Hb α-globin, HBA 52 Gly>Cys and Hb ß-globin, HBB 146 His>Asn). In terms of control samples, all the result of HbA1c were "acceptable", within the criteria of ±7% compared to IFCC RMP target values. However, percentage of "unacceptable" results of samples with Hb variants were 16% for Capillarys 2, 7% for Tina-quant, 51% for Variant II Turbo 2.0, 95% for G8 standard mode, and 89% for HA-8180. The Capillarys 2 and HA-8180 assay did not provide the results in 5 and 40 samples with Hb variants, respectively. CONCLUSIONS: HbA1c results from five routine assays in patients with relatively common Hb variants in Korea showed various degrees of bias compared to those of IFCC RMP. Therefore, laboratories should be aware of the limitation of their methods with respect to interference from Hb variants found commonly in their local population and suggest an alternative HbA1c quantification method.
Assuntos
Análise Química do Sangue/métodos , Hemoglobinas Glicadas/análise , Hemoglobinas Glicadas/genética , Análise Química do Sangue/normas , Cromatografia Líquida de Alta Pressão , Humanos , Espectrometria de Massas , Mutação , Padrões de Referência , República da CoreiaRESUMO
BACKGROUND: Monitoring tacrolimus levels is essential for successful organ transplantation. The Dimension TACR (Siemens Healthcare Diagnostics, USA) is an automated platform used to measure tacrolimus concentrations. Recently, the manufacturer started shipping an assay reagent with improved functions. We evaluated the analytical performance of the improved Dimension TACR assay. METHODS: The precision was evaluated according to the CLSI EP5-A2 guideline. Two levels of control materials were analyzed twice a day in duplicate for 20 days in the precision study. The linearity was evaluated using five levels of mixed calibrators based on the CLSI EP6-A guideline. A comparison study was conducted based on the CLSI EP9-A3 guideline using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The limit of blank (LoB), limit of detection (LoD), and limit of quantitation (LoQ) were evaluated using CLSI EP17-A2. RESULTS: In the precision analyses, the within-run, between-run, and total coefficients of variation were 5.8%, 4.6%, and 8.1% for the low level control and 4.2%, 2.8%, and 5.9% for the high level, respectively. A linear range of 1.18-8.32 ng/mL was observed. In the comparison study, the correlation coefficient, slope, and intercept were 0.9768, 1.118, and -0.251, respectively. The results of the Dimension TACR assay were slightly higher than those of LC-MS/MS (mean bias 0.64 ng/mL). The LoB, LoD, and LoQ were 0.063 ng/mL, 0.408 ng/mL, and 1.15 ng/mL, respectively. CONCLUSIONS: The Dimension TACR assay showed good precision and linearity. Although the results using the Dimension TACR assay were higher than those using mass spectrometry, the differences were acceptable clinically.