Porphyrins are natural chemicals in the body that 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 urine or blood. This article discusses the urine test.
How the Test is Performed
After you provide a urine sample, it is tested in the lab. This is called a random urine sample.
If needed, your health care provider may ask you to collect your urine at home over 24 hours. This is called a 24-hour urine sample. Your provider will tell you how to do this. Follow instructions exactly so that the results are accurate.
How to Prepare for the Test
Your provider may tell you to temporarily stop taking medicines that may affect the test results. These may include:
- Antibiotics and anti-fungal drugs
- Anti-anxiety drugs
- Birth control pills
- Diabetes medicines
- Pain medicines
- Sleep medicines
Do not stop taking any medicine without first talking to your provider.
How the Test will Feel
This test involves only normal urination and there is no discomfort.
Why the Test is Performed
Your doctor will order this test if you have signs of porphyria or other disorders that can cause abnormal urine porphyrins.
Normal results vary. In general, for a 24-hour urine test, the range is about 50 to 300 mg.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or may test different specimens. Talk to your doctor about the meaning of your specific test results.
Urine uroporphyrin; Urine coproporphyrin
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.
McPherson R, Ben-Ezra J. Basic examination of urine. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 28.
Update Date 1/27/2015
Updated by: Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.