Clinical Chemistry, Vol 25, 87-92, Copyright © 1979 by American Association for Clinical Chemistry

Erythrocyte protoporphyrin/heme ratio in the assessment of iron status

RF Labbe, CA Finch, NJ Smith, RN Doan, SK Sood and N Madan

The protoporphyrinemia of iron deficiency is well recognized. Clinically, information on the protoporphyrin/heme molar ratio in whole blood offers certain advantages over protoporphyrin measurement alone. A procedure for determining this ratio is reported. Protoporphyrin is extracted, solubilized, and measured fluorometrically. Heme (as hemin chloride) is precipitated with the blood proteins, the precipitate is dissolved in an alkaline/pyridine solvent, and the resulting bispyridine ferriprotoporphyrin is measured spectrophotometrically. The molar ratio of these two metabolites correlates well with values for plasma ferritin, plasma iron, transferrin saturation, hemoglobin, and hematocrit. In some cases the ratio increases detectably while the other variables, especially hematocrit and hemoglobin, remain normal. Evidently it is a more sensitive index to iron status. For healthy men and women, the mean ratio is 16.0 (SD, 5.3). The mean + 3 SD, or a ratio of 32, is distinctly abnormal, as shown by a confirmatory test. We validated the test by surveying routine blood specimens obtained from several population groups.

The following articles in journals at HighWire Press have cited this article:

				I J Griffin, M M Reid, K P B McCormick, and R J Cooke Zinc protoporphyrin/haem ratio and plasma ferritin in preterm infants Arch. Dis. Child. Fetal Neonatal Ed., July 1, 2002; 87(1): F49 - 51. [Abstract] [Full Text] [PDF]

				R. B. Schifman, S. L. Rivers, P. R. Finley, and C. Thies RBC Zinc Protoporphyrin to Screen Blood Donors for Iron Deficiency Anemia JAMA, October 22, 1982; 248(16): 2012 - 2015. [Abstract] [PDF]