Comparison of alkaline phosphatase assay using two different buffer systems: AMP and DEA

Abstract

Alkaline Phosphatase (ALP) enzyme estimation is used for the diagnosis in Liver Function. It is mainly assayed in the differential diagnosis of jaundice. Although many different substrates and buffers are used in the estimation, IFCC recommends one of the two buffer systems viz., Amino Methyl Propanol (AMP) and Diethanolamine (DEA) buffers with para Nitro Phenyl Phosphate (PNPP) as the substrate. The reference ranges for ALP differs mainly due to the buffers used and it is has been observed that the normal ranges are higher with DEA buffer compared with AMP buffer.  This research work is an attempt to find a quantitative relationship between the results obtained for about 250 patient’s samples using the same analyser, same company reagents but with different buffer systems.  We have found out a factor of 2.47, which should be used to convert the value obtained using AMP buffer to get the value of ALP assayed with DEA buffer.