Measurements of porphyrins and porphyrin precursors in blood, urine, and stool are the main tests for assessing people with symptoms that may be caused by a porphyria. These tests are available in many hospital and reference laboratories. Measurement of enzyme activities in cells and DNA testing for mutations are only available in specialized centers. They are most useful for assessing people who may have a family history of the disease but do not currently have symptoms.
- Measurement of porphobilinogen or PBG, a porphyrin precursor, in urine is the most important test for diagnosing an acute neurological porphyria (AIP, VP or HCP).
- Measurement of porphyrins in urine and red blood cells are used to detect and diagnose porphyrias that affect the skin (PCT is by far the most common).
- Measurement of enzyme activity in red blood cells may be used to confirm the diagnosis of AIP and to identify relatives of persons with AIP who have inherited the disease.
- Identification of specific mutations in genes (DNA testing) is the most definitive way to diagnose or exclude a porphyria in family members of an affected person, but this type of testing is not widely available at present.
See the article on Porphyrin Tests for additional details.