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Background: Cardiac troponin I (TnI) is one of the most crucial biomarkers for the management of acute coronary syndrome. However, the TnI values can vary when using commercial TnI assays from different vendors. We assessed the feasibility of TnI harmonization using plasma and serum samples., Methods: Leftover plasma and serum samples were collected from patients and stored for further analysis (n = 200). TnI measurements were performed using 3 different analyzers. The TnI values for plasma and serum were compared, and the mathematical recalibration was performed using the mean of 3 values from each analyzer as a reference value. The number of biased cases was counted before and after recalibration., Results: The final analysis was performed in a total of 140 plasma and serum samples, and constant and/or proportional differences for each analyzer were observed. Mathematical recalibration of the TnI values resulted in improved correlation to the reference values. The number of TnI values that were remote from the reference values decreased after recalibration. The effects were more evident for serum samples., Conclusions: In this study, we reassured the possibility of TnI harmonization among 3 different immunoassays using plasma and serum samples. It is important to note the differences between sample types during TnI harmonization.

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.

Protein induced by vitamin K absence (PIVKA) is measured using various assays and is used to help diagnose hepatocellular carcinoma. The present study evaluated the analytical and clinical performances of the recently released Abbott Architect PIVKA assay. Precision, linearity, and correlation tests were performed in accordance with the Clinical Laboratory Standardization Institute guidelines. Sample type suitability was assessed using serum and plasma samples from the same patients, and the reference interval was established using sera from 204 healthy individuals. The assay had coefficients of variation of 3.2-3.5% and intra-laboratory variation of 3.6-5.5%. Linearity was confirmed across the entire measurable range. The Architect PIVKA assay was comparable to the Lumipulse PIVKA assay, and the plasma and serum samples provided similar results. The lower reference limit was 13.0 mAU/mL and the upper reference limit was 37.4 mAU/mL. The ability of the Architect PIVKA assay to detect hepatocellular carcinoma was comparable to that of the alpha-fetoprotein test and the Lumipulse PIVKA assay. The Architect PIVKA assay provides excellent analytical and clinical performance, is simple for clinical laboratories to adopt, and has improved sample type suitability that could broaden the assay's utility., (© 2018 by the Association of Clinical Scientists, Inc.)

Background: Anti-hepatitis C virus antibody (anti-HCV) assays are recommended for screening HCV-infected persons. The VIDAS Anti-HCV Assay (bioMérieux, France), based on the enzyme-linked fluorescence test principle, was recently introduced in Korea. We evaluated the clinical performance of the VIDAS assay., Methods: One hundred HCV-positive and 1,002 HCV-negative blood samples confirmed by Architect anti-HCV (Abbott Laboratories, USA) and COBAS TaqMan HCV real-time PCR (Roche Diagnostics, USA) or the Procleix Ultrio Plus Assay (Gen-Probe Incorporated, USA) were obtained from the Human Serum Bank (HSB) and tested by VIDAS. In case of discrepant results, we conducted a recombinant immunoblot assay (RIBA)., Results: The agreement rates for known HCV-positive and HCV-negative samples between the VIDAS assay and the HSB testing were 100% (95% confidence interval [CI]: 96.4-100%) and 99.5% (95% CI: 98.8-99.8%), respectively. One of the five discrepant samples was positive for Core 2+ and NS3-2 2+ reactivity, two samples were negative, and the other two were indeterminate regarding NS4 2+ reactivity in RIBA. We observed a significant but weak positive correlation between the titers of VIDAS and Architect assays (r=0.315, P<0.001)., Conclusions: The VIDAS anti-HCV assay, developed on the VIDAS automated immunoassay platform based on the ready-to-use, single-sample test concept may be useful in small-to-medium-sized laboratories. It showed good agreement with Architect anti-HCV and COBAS PCR assays and is therefore useful for detection of HCV infection. Weakly test-positive (ambiguous) samples require additional testing by another anti-HCV, RIBA, or HCV RNA assay., Competing Interests: Authors' Disclosures of Potential Conflicts of Interest: No potential conflicts of interest relevant to this study were reported.

Background: Serum pepsinogen (PG) I and the PG I/PG II ratio have been used for atrophic gastritis (AG) diagnosis for decades. Low levels of PG I and/or PG I/PG II are closely related to AG and predict the risk of gastric cancer. We evaluated the performance of the chemiluminescent immunoassay-based Architect Pepsinogen I/II assay., Methods: The evaluation consisted of determination of the precision, linearity, limit of blank (LoB), limit of detection (LoD) and method comparison with Eiken and Biohit assays., Results: The total CVs were below 5% for both PG I and PG II. Acceptable linearity was observed for PG I and PG II in their respective reportable ranges. The PG I LoB was 0.317ng/mL and the PG II LoB was 0.418ng/mL, and LoDs were 0.412ng/mL and 0.497ng/mL, respectively. Correlation analysis indicated that results of the Architect assay were comparable to those of the Eiken and Biohit assays, but the three methods lead to different estimations of the cancer risk., Conclusion: The overall analytical performance of Architect Pepsinogen I/II assay is acceptable for the detection of patients with suspected AG. The categorization results of gastric cancer risk showed some difference among test methods suggesting the need for harmonization among the methods from vendors., (Copyright © 2015 Elsevier B.V. All rights reserved.)

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�00 and 17.2�37.8 pmol/L; Architect CA125 II assay, 1�00 and 3.9�,163.0 U/mL; Elecsys HE4 assay, 15�00 and 28.8�47 pmol/L; Elecsys CA125 II assay, 0.6�00 and 6.5�00 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 搇ow risk� regardless of the CA125 result. In postmenopausal woman, however, it should be reported as 搇ow risk� (CA125 < 203.0 and < 165.8 for Abbott and Roche) or 搖ndetermined� (vice-versa value). (3) If CA125 value is < 3.9 and < 6.5 for Abbott and Roche, it should be reported as 搇ow risk� (premenopausal HE4 < 51.5 and < 62.2, postmenopausal HE4 < 323.0 and < 281.5 for Abbott and Roche) or 搖ndetermined� (vice-versa value). Conclusions: New reporting strategy will provide more informative reporting of ROMA values in clinical practice. [ABSTRACT FROM AUTHOR]

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 β-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. [ABSTRACT FROM AUTHOR]