Specificity of a colorimetric paracetamol assay technique for use in cases of overdose.

A simple, economical colorimetric procedure for the determination of Paracetamol in serum or plasma (50-450 micrograms/ml) is described. Using the described method it is possible to quantify Paracetamol concentrations within 25 min which makes the technique ideal for use in an emergency-suspected overdose situation. A total of 178 drug/drug combination products were examined for possible interference with the method and of these, eight were shown to interfere significantly with the quantitative assay. However, in all cases it would be possible to correct for the interference to arrive at a semi-quantitative value for Paracetamol concentration by using the absorbance and by comparing the visible colour of the test sample with the Paracetamol standards.