• On day 1, urinate into the toilet upon arising in the morning.
• Collect all subsequent urine (in a special container) for the next 24 hours.
• On day 2, urinate into the container in the morning upon arising.
• Cap the container. Keep it in the refrigerator or a cool place during the collection period. Label the container with your name, the date, the time of completion, and return it as instructed.

This test is most often performed when porphyria or other disorders that can cause abnormal urine porphyrins is suspected.

The most important function of porphyrins is as components of heme. Heme is made from iron + protoporphyrin. Hemoglobin is made up of four heme molecules + four globin proteins. Oxygen binds to the iron in the heme molecules.

Various kinds of porphyrins exist with the same basic structure, but with slightly different chemical appearance.

Heme production involves biochemical conversion of porphyrins into delta-ALA, then to PBG, then uroporphyrin, then coproporphyrin, then protoporphyrin, and finally into the end product -- heme.

Each of these steps requires the presence of a specific enzyme. If any of the enzymes are deficient (because of a genetic disease or interference by a toxic substance), the intermediate substances build up, and a type of porphyria results.

• Random urine: negative test
• 24-hour urine: 50 - 300 mg (milligrams) per 24 hours

• Liver cancer
• Hepatitis
• Lead poisoning
• Porphyria (several types)

In specific types of porphyria, levels of ALA, uroporphyrin, and coproporphyrin may also be higher than normal.