Determination of bilirubin in capillary plasma by a direct photometric method (DPM, bilirubinometer) and the chemical determination of bilirubin in the bilirubin determination (2,5-dichlorophenyldiazonium method) in serum of venous blood samples

The determination of bilirubin in serum was performed by the 2.5-dichlorphenyldiazonium method (DPD) and in capillary plasma by the direct photometric method (DPM). Both methods showed a good precision and accuracy. The investigation was carried out in 135 samples with a bilirubin concentration up to 25 mg/dl. The comparison of the two methods in 62 samples with a bilirubin concentration up to 10 mg/dl showed a correlation coefficient of r = 0.862 and in 73 samples with a bilirubin concentration between 10 and 25 mg/dl a correlation coefficient of r = 0.893. In 29 cases (21.5%) we found differences between the two methods of 1.5-4.0 mg/dl. Most of them were in the critical higher range. Discussion of the DPD and DPM methods.