Background Serum carbohydrate antigen 19-9 (CA19-9) is widely used in the management of pancreatic diseases, but results often vary across immunoassay platforms. This study sought to describe how the values obtained by chemiluminescent immunoassay (CLIA) and electrochemiluminescent immunoassay (ECLIA) differ, to assess whether discrepancies vary across concentration ranges, and to identify clinical factors potentially contributing to this variability.Methods We examined 1,760 paired samples measured simultaneously by CLIA (Abbott Alinity i) and ECLIA (Roche Cobas e801) during a transition period. To assess agreement between assays, correlation analysis, Passing-Bablok regression, and Bland-Altman analysis were performed on log10-transformed data. Subgroup comparisons were made by CA19-9 concentration, disease category, and hepatobiliary enzyme status. Multivariable regression was used to explore independent factors associated with the magnitude of inter-assay differences.Methods We examined 1,760 paired samples measured simultaneously by CLIA (Abbott Alinity i) and ECLIA (Roche Cobas e801) during a transition period. To assess agreement between assays, correlation analysis, Passing-Bablok regression, and Bland-Altman analysis were performed on log10-transformed data. Subgroup comparisons were made by CA19-9 concentration, disease category, and hepatobiliary enzyme status. Multivariable regression was used to explore independent factors associated with the magnitude of inter-assay differences.Results Correlation between CLIA and ECLIA was strong (r = 0.94, rho = 0.89) although a concentration-dependent bias was observed with CLIA yielding higher values at higher concentrations, whereas ECLIA tended to yield higher values at lower concentrations. Discrepancies were greater in pancreatic cancer samples in those with elevated ALP or gamma-GT, and at higher concentrations (CLIA >= 1000 U/mL). Older age, female sex, pancreatic cancer, and elevated hepatobiliary enzymes were independently associated with larger assay differences (adjusted R2 = 0.13).Conclusions Despite good overall agreement, the two methods showed variability that could affect clinical interpretation, especially in low or high concentration ranges. When assay changes are unavoidable, using method-specific reference ranges or confirming results near decision thresholds may help ensure consistent interpretation.
Objective To assess the analytical performance and diagnostic accuracy of an automated analyzer HELIOS in external proficiency testing for diagnosing autoimmune disorders based on antinuclear antibody (ANA) images and titer values. Methods Total 09 CAP shipments over the period of 03 years were included in our study, comprising 05 samples in each shipment making a total of 45 samples. All samples were analyzed on HELIOS by the technique of Indirect Immunofluorescence (IFA) having built-in library for ANA image comparison and end-point titer estimation. Results The data showed that there was 100% agreement with the positivity and negativity of the PT samples in detecting autoimmune disorders; however, for ANA pattern agreement, it was an average of 90.3% compared to peer mean. The most frequent ANA pattern in all 3 years was nuclear homogenous (40%) followed by nuclear speckled (32%). However, for end-point titer, there is a marked difference of mutual agreement with the PT peer group showing the lowest harmony of 35.3% in 2022 which was reported with titer of 5120; however, peer group reported titer was <= 640. Thus, the analyzer has a limitation in evaluating end-point titer and it should always be critically evaluated by the pathologist before final approval. Conclusion HELIOS has an acceptable performance in detecting autoimmune disorders and ANA pattern identification; however, for end-point titer, there were many variations for which manual dilutions should be done in routine for accurate analysis of results.
Background Low-density lipoprotein cholesterol (LDL-C) and non-HDL cholesterol (non-HDL-C) reflect cholesterol mass, whereas apolipoprotein B (ApoB) reflects atherogenic particle number. We examined residual ApoB elevation after both cholesterol thresholds had been met and its distribution across triglyceride levels. Methods We analyzed the 2005–2016 fasting subsample of the National Health and Nutrition Examination Survey (NHANES) among adults aged 30–79 years. The primary subgroup had LDL-C <2.59 mmol/L [100 mg/dL] and non-HDL-C <3.36 mmol/L [130 mg/dL]; residual elevation was defined as ApoB ≥0.90 g/L [90 mg/dL]. NHANES estimates and regressions accounted for the complex survey design. CHNS 2009 provided an unweighted consistency assessment. Results Of 10,451 NHANES participants, 3,132 met both thresholds and 163 had ApoB ≥0.90 g/L. Weighted prevalence was 5.4% (95% CI 4.4–6.4), rising to 18.2% with triglycerides ≥1.69 mmol/L [150 mg/dL], compared with 2.9% below this threshold. The clinical model yielded an odds ratio of 6.23 (95% CI 3.68–10.53; P < 0.001). Prevalence varied by ApoB threshold (22.9% at ≥0.80 g/L; 0.9% at ≥1.00 g/L). In CHNS, corresponding triglyceride-stratified prevalences were 8.9% and 1.9%. Conclusions Residual ApoB elevation after simultaneous LDL-C and non-HDL-C threshold attainment was concentrated in adults with higher triglycerides. Triglyceride levels offer a readily available means of identifying a subgroup with substantially greater yield from ApoB measurement.
