Definition of Porphyrins - blood:

Porphyrins are a group of chemicals that help form many important substances in the body, including hemoglobin, the protein in red blood cells that carries oxygen in the blood.

This article discusses the test to measure the total amount of porphyrins in your blood.

See also: Porphyrins - urine

How the test is performed:

A blood sample is needed. For information on how this is done, see: Venipuncture

The sample is then placed in ice and taken immediately to the laboratory. Three porphyrins can normally be measured in small amounts in human blood. They are:

• Coproporphyrin
• Protoporphyrin (PROTO)
• Uroporphyrin

Protoporphyrin is normally found in the highest amount. More tests are needed to show the levels of specific porphyrins.

How to prepare for the test:

You should not eat for 12 - 14 hours before this test. You may drink water right before the test. Failure to follow these restrictions may affect the test results.

How the test will feel:

When the needle is inserted to draw blood, you may feel moderate pain, or only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the test is performed:

This test is used to diagnose porphyrias, a group of rare disorders often passed down through family members.

It may also be used along with other tests to diagnose lead poisoning and certain nervous system and skin disorders.