Porphyrins - blood
Porphyrins help form many important substances in the body. One of these is hemoglobin, the protein in red blood cells that carries oxygen in the blood.
Porphyrins can be measured in the blood or the urine.
Protoporphyrin levels; Porphyrins - total; Coproporphyrin levels; PROTO test
How the Test is Performed
A blood sample will be taken from your vein.
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:
- Protoporphyrin (PROTO)
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. Your test results may be affected if you do not follow these steps.
How the Test will Feel
You may feel a little pain or a sting when the needle is inserted to draw blood. You may feel throbbing at the site afterward.
Why the Test is Performed
This test is used to diagnose porphyrias. This is 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.
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.
The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.
What Abnormal Results Mean
Increased levels of coproporphyrins may be a sign of:
Increased protoporphyrin levels may be a sign of:
- Anemia of chronic disease
- Congenitalerythropoietic protoporphyria
- Increased erythropoiesis
- Iron deficiency anemia
- Lead poisoning
- Sideroblastic anemia
- Variegate porphyria
Increased uroporphyrin levels may be a sign of:
- Congenital erythropoietic porphyria
- Porphyria cutanea tarda
Veins and arteries vary in size so taking a blood sample may be harder in some people than others.
Other slight risks of having blood drawn 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)
Anderson K. The porphyrias. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 217.
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, eds. Hematology: Basic Principles and Practice. 6th ed. Philadelphia, PA: Saunders Elsevier; 2012:chap 36.