[Determination of erythrocyte protoporphyrin by a spectrofluorometry method]

Erythrocyte protoporphyrin (EP) measurement is useful for the diagnosis of protoporphyrin, iron deficiency or lead poisoning. The authors described a manual procedure for the spectrofluorimetric determination of EP. Erythrocytes were used, instead of whole blood. The following steps were performed: treatment with celite suspension, extraction using ethylacetate/acetic acid, estimation of the fluorescence of protoporphyrin IX extracted in HCl. Analytical results are following: a low detection limit (0.045 mumol/l), a linear response up to 2 mumol/l, within run and day-to-day precision respectively better than 3.5 p. cent and 5.8 p. cent. The procedure with predilution led to no significant difference with the spectrophotometric reference method (student t-test, t: 0.85) up to 42 mumol/l. Concentrations of EP according to age were studied for children (0.0470-1.000 mumol/l), middle-aged subjects (0.390-0.880) and elderly subjects (0.340-1.040). The proposed method is accurate, rapid and available for routine measurements.