Analytical performance evaluation of sensitive and old generation reagent in routine practical use: estradiol experience.

Evaluation of the analytical performance of tests in medical laboratories is important. Total Error (TE) and sigma analysis have been used as a quantitative indicator of quality for many years. The aim of this study is to evaluate the analytical performance of Beckman Coulter Access Estradiol (E2) and Sensitive E2 reagents. Analytical performance of two reagents were evaluated with TE, six sigma and measurement uncertainty values. Two Beckman Coulter Unicel DxI-800 autoanalyzers (A1 and A2) included in the study. Quality control data between December 2017 and December 2019 were used. CLIA-2019 values were used for total allowable error (TEa) limits. Uncertainty values were calculated with ISO/TS 20914. The median TE of the old generation and sensitive E2 reagent were 27.46% (between 13.49 and 48.88) and 11.16% (between 7.08 and 24.81), respectively (p < .005) The process sigma results were below 3 sigma in all months with the old reagent, whereas with the new reagents it was seen to be above 3 sigma in 11 of 12 months for both autoanalyzers. Uncertainty of old reagent is higher than new reagent. Imprecisions decrease as concentration increases with both reagents. The uncertainty values of low concentration levels are greater than high concentration levels. In conclusion, in both auto analyzers, Sensitive E2 reagent was found to have better performance than old reagent in terms of TE, process sigma and measurement uncertainty. We believe that the sensitive E2 reagent still needs further improvement for patients who have low E2 levels.

The role of maternal serum catestatin in the evaluation of preeclampsia and fetal cardiac functions

Objective: To compare the maternal serum catestatin (CST) levels in pregnant women with preeclampsia (PE) and with normal blood pressure and evaluate the relationship between the maternal serum CST levels and fetal cardiac functions. Materials and Methods: This cross-sectional study was conducted on 27 women with early-onset PE (EOPE), 28 women with late-onset PE (LOPE), and 28 healthy pregnant women. Maternal serum CST levels were measured using the enzyme-linked immunosorbent assay kits. Fetal cardiac functions were evaluated using the cardiac Doppler. Results: Maternal serum CST levels were lower in the EOPE group; however, no statistically significant difference was found between the groups. Compared with the other two groups, a statistically significant difference was found in the fetal E/A ratio and myocardial performance index (MPI) values of the EOPE group (p=0.013, p=0.002, p=0.005, p<0.001, respectively). The fetal E/A ratio was positively correlated with the maternal serum CST levels in both the PE and control groups (p<0.001, p<0.001). The fetal isovolumetric relaxation time and MPI values were negatively correlated with maternal serum CST levels in both the PE and control groups (p<0.001, p=0.001, p<0.001, and p=0.002, respectively). Conclusion: Lower CST levels are associated with fetal cardiovascular dysfunction, thus CST can be a critical biochemical marker in fetal cardiac function evaluation.