Determination of blood concentration of valproic acid--a comparative study of methods

The substrate labeled fluorescent immunoassay technique (SLFIA method) was examined in terms of clinical utility for the determination of blood levels of valproic acid (VPA) by comparing it to the enzyme-multiplied immunoassay technique (EMIT method). Both accuracy and precision were very high, and the correlation between the two was excellent (r = 0.985). Practically, the presence of hemoglobin in the sample had little influence on the accuracy. Results show that the SLFIA method is a useful means for the determination of blood concentration of VPA in epileptic patients.