Porphyrins - blood

• Alternative Names

  Protoporphyrin levels; Porphyrins - total; Coproporphyrin levels; PROTO test

• How the test is performed

  Blood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

  Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.

  Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

  In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.

  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. Additional 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.

• Normal Values

  This test specifically measures total porphyrin levels, but reference values (a range of values seen in a group of healthy people) for the individual components are also included:

  • Total porphyrin levels: 16 to 60 mcg/dL
  • Coproporphyrin levels: < 2 mcg/dL
  • Protoporphyrin levels: 16 to 60 mcg/dL
  • Uroporphyrin levels: < 2 mcg/dL

  Note: mcg/dL = micrograms per deciliter

  Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

• What abnormal results mean

  Increased levels of coproporphyrins may indicate:

  • Congenital erythropoietic porphyria
  • Hepatic coproporphyria
  • Sideroblastic anemia

  Increased protoporphyrin levels may indicate:

  • Anemia of chronic disease
  • Erythropoietic protoporphyria
  • Increased erythropoiesis
  • Infection
  • Iron deficiency anemia
  • Lead poisoning
  • Sideroblastic anemia
  • Thalassemia
  • Variegate porphyria

  Increased uroporphyrin levels may indicate:

  • Congenital erythropoietic porphyria
• What the risks are

  Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

  Other risks associated with having blood drawn are slight but may include:

  • Excessive bleeding
  • Fainting or feeling light-headed
  • Hematoma (blood accumulating under the skin)
  • Infection (a slight risk any time the skin is broken)
• References

  Anderson KE. The porphyrias. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 229.

Review Date: 8/9/2009

Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.