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 individual enzyme activities and DNA testing for mutations are only available in a limited number of specialized centers. They are most useful for assessing people who have a family history of the disease but do not currently have symptoms.
- Measurement of porphobilinogen, 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 is 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 (DNA testing) is the most definitive way to diagnose or exclude a porphyria in family members of an affected person. This type of testing is not widely available at present.
See the article on Porphyrin Tests for additional details.