Measurement of Serum Total Bilirubin in Jaundiced Newborns by Direct Spectrophotometric Micro-Technique and Diazo Method.

Abstract

Background : Serum total billirubin (STB) concentrations are measured by Diazo Methods (DMs) in clinical laboratories in third world countries. However, several reports across the world suggest that these methods are associated with numerous problems. There is a need to search for an alternative method specific for neonatal bilirubin analysis. The aim of the present study was to assess a direct Spectrophotometric micro-technique (DSMT) with a view to recommending its application or otherwise for the routine estimation of serum bilirubin (SB).
Materials and methods: SB concentrations were estimated by both DM and DSMT in 100 (50 males and 50 females), full – term (n±84) and pre-term (n=16) jaundiced newborns, admitted to the Special Care Baby Unit (SCBU) of ABUTH, Zaria. Capillary and venous blood specimens were obtained for the measurement of STB concentrations by DSMT and DM respectively. The data obtained were analyzed using SPSS 11.0 for Windows (SPSS, Chicago, IL). The results of STB concentrations obtained by DSMT were compared with those obtained by DM using Student’s t- test statistic method. Correlation of the two methods was carried out using Pearson’s linear correlation. A p-value of equal to or less than 0.05 (p< 0.05) was considered as statistically significant.
Results: The mean values of STB concentrations obtained using DSMT and DM were 242 ± 85 and 215 ± 90 μmol/L respectively. The difference between these values was statistically significant (p <0.05). The plot of the two methods showed a linear significant correlation (r = 0.999, p < 0.001).
Conclusion: DSMT for neonatal bilirubin analysis is fast, simple to perform and gives more accurate SB values than DM, which under estimated the results. It is therefore recommended that DSMT for SB analysis be used for routine clinical laboratory applications.

KEYWORD: Direct spectrophotometric micro-technique; diazo method; serum total bilirubin; jaundiced newborns