ABSTRACT
High blood concentrations of bilirubin are toxic to the brain and may cause kernicterus. Therefore, determination of bilirubin levels is performed for many newborns, and several different methods are available. We compared 2 standards used for bilirubin determination among newborns under routine conditions, to define their sequence of use. This study was carried out during the period from March 2003 and December 2006 at the Vaccine and Sera institute / Ministry of Health, Baghdad, Iraq. Bilirubin concentrations were determined with 2 standards: local standard [prepared from chemical compound which has a broad spectral absorption peak at 460 nm, this solution is stable indefinitely], and randox standard [obtained industrially by extraction of either cattle or pig bile, or bovine, and it can be isolated as light-sensitive orange-red crystals with certain "stability" about 24 hours]. A total of 100 samples were obtained. The 2 standards showed very strong correlations [correlation coefficients 0.9999] with each other; and; their means were used as comparison values. In the routine care of newborns, the measurement of total bilirubin by bilirubinometer provides better agreement with local standard than does randox and it is the first choice. Testing specimens based on human serum would provide meaningful information regarding the accuracy and precision of total bilirubin assays. The ability to grade proficiency testing participants for accuracy, using target values determined by the reference method, could become a valuable contribution toward improving the quality of bilirubin assays, which is essential for the management of neonatal hyperbilirubinemia. Local standard give accurate information on bilirubin concentrations as do randox standard did, and presented the best results