Free erythrocyte porphyrins

General Information

Determination of free erythrocyte protoporphyrins is recommended in the diagnostics of erythrocyte protoporphyria and X-linked protoporphyria.

Protoporphyrias are disorders caused by genetic defects in heme-synthesizing enzymes in the erythrocyte. Depending on which enzyme deficiency is expressed, different porphyrins and their precursors accumulate in different ways. Depending on which porphyrin accumulates in the erythrocyte and which heme precursors are excreted in the urine, different types of porphyrias are distinguished.

Determination of erythrocyte porphyrin levels is very sensitive in patients with a presumptive diagnostics of erythrocyte or X-linked protoporphyria. The clinical manifestations of both these porphyrias are the same

Iron deficiency in the body inhibits the terminal processes of heme synthesis and causes the accumulation of free erythrocyte protoporphyrins in erythrocyte progenitor cells. The cellular contents remain unchanged throughout the life of the erythrocyte. The function of free erythrocyte protoporphyrins is iron binding in the process of erythrocyte formation. The concentration of free erythrocyte protoporphyrins is increased during lead intoxication. The level of free erythrocyte protoporphyrins is also elevated in the diagnostics of erythrocyte protoporphyria and X-linked protoporphyria. Both of them are genetic photodermatoses caused by a deficiency of heme-synthesizing enzymes.

Erythrocytic protoporphyria develops in partial deficiency of the enzyme ferrochelatase. And X-linked protoporphyria is the result of a mutation in the ALAS2 gene. In both cases, erythrocyte protoporphyrins, which are released from the liver and blood vessel endothelium, accumulate in the blood plasma. When exposed to sunlight, protoporphyrins are activated and cause tissue damage and pain syndrome.

When is the survey conducted?

• Iron deficiency anemia
• Chronic poisoning with heavy metals, especially lead, as well as organic chemical agents
• Congenital erythropoietic porphyria – a congenital disease caused by uroporphyrinogen 3 synthase deficiency
• Hepatoerythropoietic porphyria – an autosomal recessive disease caused by uroporphyrinogen decarboxylase deficiency

Patient preparation – 24 hours before taking the sample, alcohol intake is prohibited

Research material – Venous blood

Referral norm: <20 mcg/dL 

Alcohol suppresses the activity of enzymes, which may cause a false positive result.