[A routine method for thin layer chromatographic determination of urocanic acid in blood samples impregnated on filter paper cards (author's transl)].

A method is described for mass screening at birth for histidinaemia. Blood samples are collected on filter paper cards, as used in the Guthrie test. These samples are transferred, together with standards of histidine and urocanic acid, to thin layer chromatography plates by a type of sandwich technique. The plates can be evaluated semiquantitatively, after development and detection with Pauly's reagent. The detection limit for both substances is less than 10 mg/1 (60 mumol/1). Greater sensitivity and absence of interference, greatly reduce the proportion of equivocal results compared with the Guthrie test.