Erythropoietic protoporphyria. III. Photohemolysis

Abstract

Abnormal in-vitro red cell photohemolysis can be used as a diagnostic aid for erythropoietic protoporphyria. Photohemolysis is regularly present in erythropoietic protoporphyria and is negligible in normal subjects, in patients with polymorphic light eruption and in lead poisoning. A simple technique consists of irradiating a suspension of red cells diluted 1:500 in Ringer''s solution by using a modified X-ray view box equipped with blacklight fluorescent tubes to serve as the irradiation apparatus. After three hours of exposure pres-cence of photohemolysis is determined by direct visual or by photometric examination of the supernatant fluid. The technique does not involve a chemical or fluorometric analysis.