[Fluorimetric assay of serum 5-fluorocytosine].

A manual and fast procedure for the fluorimetric determination of 5-fluorocytosine in the serum, after extraction by chloroform is described. The intra-assay variation was between 3,1 and 4,1%; the inter-assay variation was 4,8%. The results obtained are in good agreement with those obtained by the microbiological method. The determination of 5-fluorocytosine by this method is not possible if the sample contains ketoconazole or 5-fluorouracil.