The Direct Spectrophotometric Method Is Reliable for Initial Assessment of Total Bilirubin in Neonatal Venous Plasma.

OBJECTIVE: To determine the consistency of bilirubin values between the direct spectrophotometric (DS) and colorimetric diazo (diazo) methods in neonatal venous plasma specimens. METHODS: We measured the total bilirubin via the DS and diazo methods in 255 neonatal venous plasma specimens and compared the overall and subgroup results. RESULTS: Slight underestimation of total bilirubin values in most specimens using the DS method was observed, with higher mean biases found in higher concentrations. Significantly high positive correlations were found in all groups in which most of the different values were within the limits of agreement. DS cutoff of > 12 mg/dL showed 100% for all predictive indices in comparison with the diazo cutoff > 15 mg/dL. CONCLUSIONS: Measurement of total bilirubin in neonatal venous plasma using the DS method had favorable agreement and high correlation with the diazo method. Therefore, the direct spectrophotometric method can be used as a reliable screening method.

Strong correlation and high comparability of capillary electrophoresis and three different methods for HbA1c measurement in a population without hemoglobinopathy.

The present study aimed to investigate the comparability of capillary electrophoresis (CE) and three different methods for HbA1c measurement. The 270 whole blood samples with normal hemoglobin profiles were analyzed for HbA1c values by the Roche turbidimetric inhibition immunoassay (TINIA), the Mindray enzymatic assay (EA), the Arkray high-performance liquid chromatography (HPLC) in comparison with the Sebia CE. The within-laboratory coefficient of variation of all four methods was within the accepted goal (<2%), showing good performance of all of these methods. Pairwise comparisons of HbA1c values obtained by CE and other methods were determined in both total group and subgroups (HbA1c levels of <6.5%, 6.5-8% and >8%). Mean differences of HbA1c values in all groups were very small in which the mean HbA1c value measured by EA was lower while those by TINIA and HPLC were higher than that of CE. The majority of different values were within the limits of agreement in Bland-Altman analysis, indicating good agreement between CE and the others. Less than 5% of percentage differences were out of the total allowable error limit in all groups, showing that differences of HbA1c values between CE and other methods were not clinically significant. Pairwise comparisons of HbA1c values of CE and the others in Passing-Bablok regression and Spearman rank correlation studies displayed high concordance and strong correlation in all groups. In conclusion, the present study showed strong correlation, high comparability and consistent results for HbA1c measurement between capillary electrophoresis and the other three different methods.