<prompt> Red cell Protoporphyrin levels more than 100 microgram dL is suggestive of which of the following?Iron deficiency anemiaLead poisoningMyelodysplasiaAll  <response>: Ans. a Iron deficiency anemia Ref. Harrison 18th ch. 103RED CELL PROTOPORPHYRIN LEVELS Protoporphyrin is an intermediate in the pathway to heme synthesis. Under conditions in which heme synthesis is impaired, protoporphyrin accumulates within the red cell. This can reflect an inadequate iron supply to erythroid precursors to support hemoglobin synthesis. Normal values are less than 30 microgdL of red cells. In iron deficiency, values in excess of 100 microgdL are seen. The most common causes of increased red cell protoporphyrin levels are absolute or relative iron deficiency and lead poisoning. 