Background: Procalcitonin (PCT) is a crucial biomarker for diagnosing sepsis and managing antibiotic therapy. This study evaluated the analytical performance and comparability of the Access PCT and Elecsys BRAHMS PCT assays. Methods: The precision, detection capability, linearity, and reference range of both assays were assessed. A comparative analysis included 182 patient samples categorized into four risk groups to compare the results between Access PCT and Elecsys BRAHMS PCT assays. Results: The Access PCT assay demonstrated precision within the manufacturer’s threshold, and its detection capabilities were verified. This assay exhibited excellent linearity and appropriate reference intervals. Comparative analysis indicated that the Access PCT assay reported higher overall PCT levels than the Elecsys BRAHMS assay, with high agreement between the assays (κ=0.941). However, the biases varied across different PCT concentration intervals. Conclusions Both the Access PCT and Elecsys BRAHMS PCT assays performed robustly with notable concordance but varying biases at different concentration intervals. The observed biases require careful consideration in clinical decision-making, especially when adopting novel assay systems. Standardizing the calibration across different platforms is recommended to improve assay comparability.

Background: Procalcitonin (PCT) is a crucial biomarker for diagnosing sepsis and managing antibiotic therapy. This study evaluated the analytical performance and comparability of the Access PCT and Elecsys BRAHMS PCT assays. Methods: The precision, detection capability, linearity, and reference range of both assays were assessed. A comparative analysis included 182 patient samples categorized into four risk groups to compare the results between Access PCT and Elecsys BRAHMS PCT assays. Results: The Access PCT assay demonstrated precision within the manufacturer’s threshold, and its detection capabilities were verified. This assay exhibited excellent linearity and appropriate reference intervals. Comparative analysis indicated that the Access PCT assay reported higher overall PCT levels than the Elecsys BRAHMS assay, with high agreement between the assays (κ=0.941). However, the biases varied across different PCT concentration intervals. Conclusions Both the Access PCT and Elecsys BRAHMS PCT assays performed robustly with notable concordance but varying biases at different concentration intervals. The observed biases require careful consideration in clinical decision-making, especially when adopting novel assay systems. Standardizing the calibration across different platforms is recommended to improve assay comparability.

Background: Procalcitonin (PCT) is a crucial biomarker for diagnosing sepsis and managing antibiotic therapy. This study evaluated the analytical performance and comparability of the Access PCT and Elecsys BRAHMS PCT assays. Methods: The precision, detection capability, linearity, and reference range of both assays were assessed. A comparative analysis included 182 patient samples categorized into four risk groups to compare the results between Access PCT and Elecsys BRAHMS PCT assays. Results: The Access PCT assay demonstrated precision within the manufacturer’s threshold, and its detection capabilities were verified. This assay exhibited excellent linearity and appropriate reference intervals. Comparative analysis indicated that the Access PCT assay reported higher overall PCT levels than the Elecsys BRAHMS assay, with high agreement between the assays (κ=0.941). However, the biases varied across different PCT concentration intervals. Conclusions Both the Access PCT and Elecsys BRAHMS PCT assays performed robustly with notable concordance but varying biases at different concentration intervals. The observed biases require careful consideration in clinical decision-making, especially when adopting novel assay systems. Standardizing the calibration across different platforms is recommended to improve assay comparability.

Background: Procalcitonin (PCT) is a crucial biomarker for diagnosing sepsis and managing antibiotic therapy. This study evaluated the analytical performance and comparability of the Access PCT and Elecsys BRAHMS PCT assays. Methods: The precision, detection capability, linearity, and reference range of both assays were assessed. A comparative analysis included 182 patient samples categorized into four risk groups to compare the results between Access PCT and Elecsys BRAHMS PCT assays. Results: The Access PCT assay demonstrated precision within the manufacturer’s threshold, and its detection capabilities were verified. This assay exhibited excellent linearity and appropriate reference intervals. Comparative analysis indicated that the Access PCT assay reported higher overall PCT levels than the Elecsys BRAHMS assay, with high agreement between the assays (κ=0.941). However, the biases varied across different PCT concentration intervals. Conclusions Both the Access PCT and Elecsys BRAHMS PCT assays performed robustly with notable concordance but varying biases at different concentration intervals. The observed biases require careful consideration in clinical decision-making, especially when adopting novel assay systems. Standardizing the calibration across different platforms is recommended to improve assay comparability.

Background: Procalcitonin (PCT) is a crucial biomarker for diagnosing sepsis and managing antibiotic therapy. This study evaluated the analytical performance and comparability of the Access PCT and Elecsys BRAHMS PCT assays. Methods: The precision, detection capability, linearity, and reference range of both assays were assessed. A comparative analysis included 182 patient samples categorized into four risk groups to compare the results between Access PCT and Elecsys BRAHMS PCT assays. Results: The Access PCT assay demonstrated precision within the manufacturer’s threshold, and its detection capabilities were verified. This assay exhibited excellent linearity and appropriate reference intervals. Comparative analysis indicated that the Access PCT assay reported higher overall PCT levels than the Elecsys BRAHMS assay, with high agreement between the assays (κ=0.941). However, the biases varied across different PCT concentration intervals. Conclusions Both the Access PCT and Elecsys BRAHMS PCT assays performed robustly with notable concordance but varying biases at different concentration intervals. The observed biases require careful consideration in clinical decision-making, especially when adopting novel assay systems. Standardizing the calibration across different platforms is recommended to improve assay comparability.

The adoption of high-sensitivity flow cytometry (HSFC) in routine laboratory settings has been slow owing to concerns regarding the reliability and reproducibility of results. Validation is an essential prerequisite for conducting assays, and implementing the CLSI guidelines has been confusing, primarily because many aspects are not yet established. We aimed to validate an HSFC protocol for detecting follicular helper T (Tfh) cells in a real-world laboratory environment. The analytical validity of the Tfh cell panel was ensured through rigorous testing, including evaluations of precision, stability, carryover, and sensitivity, following the CLSI H62 guidelines. We found that Tfh cells, present in very small numbers in the blood, could be sufficiently detected through HSFC, and concerns about the reliability and reproducibility of the results in real-world laboratories could be solved through systematic validation. Establishing the lower limit of quantification (LLOQ) is a critical step in HSFC evaluations. By selecting an appropriate sample, for example, collecting residual cells from CD4 isolation in our experiment and using them as low-level samples, the LLOQ could be accurately established. The strategic validation of flow cytometry panels can facilitate the adoption of HSFC in clinical laboratories, even with limited resources.

Various methodologies for the genetic analysis of longitudinal data have been proposed and applied to data from large-scale genome-wide association studies (GWAS) to identify single nucleotide polymorphisms (SNPs) associated with traits of interest and to detect SNP-time interactions. We recently proposed a grid-based Bayesian mixed model for longitudinal genetic data and showed that our Bayesian method increased the statistical power compared to the corresponding univariate method and well detected SNP-time interactions. In this paper, we further analyze longitudinal obesity-related traits such as body mass index, hip circumference, waist circumference, and waist-hip ratio from Korea Association Resource data to evaluate the proposed Bayesian method. We first conducted GWAS analyses of cross-sectional traits and combined the results of GWAS analyses through a meta-analysis based on a trajectory model and a random-effects model. We then applied our Bayesian method to a subset of SNPs selected by meta-analysis to further discover SNPs associated with traits of interest and SNP-time interactions. The proposed Bayesian method identified several novel SNPs associated with longitudinal obesity-related traits, and almost 25% of the identified SNPs had significant p-values for SNP-time interactions.

Background: We sought to compare the performance of three commercially available automated urine sediment analyzers that represent the current urine sediment analysis technology. Methods: A total of 232 patient samples were analyzed using manual microscopy and three automated analyzers: IRIS Iq200 (Beckman Coulter, USA), UF-1000i (Sysmex, Japan), and Cobas u701 (Roche, Switzerland). We analyzed precision, linearity, carry-over, concordance rate, and agreement between the three analyzers and manual microscopy. Results: The repeatability and within-laboratory precision showed results similar to those of previous studies. All analyzers showed excellent linearity. The carry-over rates were within 1%. The correlation coefficient (r) between the three analyzers and manual microscopy was good. Regarding red blood cell (RBC), the UF-1000i showed a better concordance rate (90.52%) with manual microscopy than the other two analyzers and the agreement was substantial for UF-1000i (κ=0.63) and IRIS Iq200 (κ=0.61). Regarding white blood cell (WBC), Cobas u701 showed the best concordance rate (96.55%) and the agreement was moderate for IRIS Iq200 (κ=0.57) and Cobas u701 (κ=0.56), and fair for UF-1000i (κ=0.47). Regarding epithelial cell (EPI), IRIS Iq200 showed the highest concordance rate (99.2%) and the agreement was moderate for IRIS Iq200 (κ=0.59) and Cobas u701 (κ=0.54), and fair for UF-1000i (κ=0.40). Conclusions IRIS Iq200 offered the best agreement with manual microscopy for WBC and EPI count, while UF-1000i showed a better agreement for RBC count. The agreement is insufficient for fully replacing the manual microscopy.

Background: We sought to compare the performance of three commercially available automated urine sediment analyzers that represent the current urine sediment analysis technology. Methods: A total of 232 patient samples were analyzed using manual microscopy and three automated analyzers: IRIS Iq200 (Beckman Coulter, USA), UF-1000i (Sysmex, Japan), and Cobas u701 (Roche, Switzerland). We analyzed precision, linearity, carry-over, concordance rate, and agreement between the three analyzers and manual microscopy. Results: The repeatability and within-laboratory precision showed results similar to those of previous studies. All analyzers showed excellent linearity. The carry-over rates were within 1%. The correlation coefficient (r) between the three analyzers and manual microscopy was good. Regarding red blood cell (RBC), the UF-1000i showed a better concordance rate (90.52%) with manual microscopy than the other two analyzers and the agreement was substantial for UF-1000i (κ=0.63) and IRIS Iq200 (κ=0.61). Regarding white blood cell (WBC), Cobas u701 showed the best concordance rate (96.55%) and the agreement was moderate for IRIS Iq200 (κ=0.57) and Cobas u701 (κ=0.56), and fair for UF-1000i (κ=0.47). Regarding epithelial cell (EPI), IRIS Iq200 showed the highest concordance rate (99.2%) and the agreement was moderate for IRIS Iq200 (κ=0.59) and Cobas u701 (κ=0.54), and fair for UF-1000i (κ=0.40). Conclusions IRIS Iq200 offered the best agreement with manual microscopy for WBC and EPI count, while UF-1000i showed a better agreement for RBC count. The agreement is insufficient for fully replacing the manual microscopy.