A micromethod for free erythrocyte porphyrins: the FEP test.

Abstract A simple and rapid micromethod for the measurement of free erythrocyte porphyrins (FEP test) from 20 μl of blood is described. The technique utilizes a simplified rapid extraction in combination with the greater sensitivity of the fluorometer. The results obtained with this micromethod compare favorably with those of a classical technique. The free erythrocyte porphyrin concentration increases exponentially when the blood lead level is increased. The micromethod (FEP test) appears to be a promising tool to screen children for lead poisoning.