What are Porphyrins?

Porphyrins are natural chemicals in the body that help form many important substances in the body such as hemoglobin, the protein in red blood cells that carries oxygen in the blood. Porphyrins are normally present at low concentrations in blood and other body fluids, such as urine.

Why is this test performed?

Porphyrin tests are used to help diagnose and monitor a group of disorders called porphyrias. Porphyrias are a group of rare disorders. An important part of hemoglobin, called heme, is not made properly. Heme is also found in myoglobin, a protein found in certain muscles. There are seven types of porphyria, and each one is associated with a different enzyme deficiency. Most porphyrias are inherited, the result of a gene mutation. They may be classified according to the signs and symptoms of the disease as neurological, cutaneous, or both.

What are signs and symptoms?

The porphyrias that cause neurological symptoms present with acute attacks lasting days or weeks. Signs and symptoms during the attack include abdominal pain, constipation, confusion, hallucinations, and/or seizures. There are four neurologic porphyrias: acute intermittent porphyria (AIP), variegate porphyria (VP), hereditary coproporphyria (HCP), and the very rare ALA dehydratase deficiency porphyria (ADP). Some cases of VP and HCP may also have skin-related symptoms.

Optimal results:

Optimal results vary depending on the type of porphyrin tested. In general, for a 24-hour urine test of total porphyrins, the range is about 23.3 – 132.4 mcg/g creat.

References: 

1. Fuller SJ, Wiley JS. Heme biosynthesis and its disorders: porphyrias and sideroblastic anemias. In: Hoffman R, Benz EJ Jr, Silberstein LE, Heslop HE, Weitz JI, Anastasi J, eds. Hematology: Basic Principles and Practice. 6th ed. Philadelphia, PA: Elsevier Saunders; 2013:chap 36.
2. Habif TP. Light-related diseases and disorders of pigmentation. In: Habif TP, ed. Clinical Dermatology: A Color Guide to Diagnosis and Therapy. 6th ed. Philadelphia, PA: Elsevier; 2016:chap 19.
3. Hift RJ. The porphyrias. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 210.