porphyrin_tests
Reviewed
Also called: protoporphyrin, protoporphyrin, blood, protoporphyrin, stool, porphyrins, feces, uroporphyrin, porphyrins, urine
Porphyrin tests measure the level of porphyrins in your blood, urine, or stool. Your body uses porphyrins to make heme, a part of hemoglobin. A small amount is normal, but high levels may indicate a type of porphyria, a group of rare disorders that are usually inherited. These tests help diagnose or monitor all types of porphyria.
Specimen: blood, urine (24-hour or random), or stool
Why this test may be ordered
- To help diagnose or monitor all types of porphyria
- If you have symptoms of acute porphyria (e.g., abdominal pain, constipation, nausea, vomiting, mental changes, red or brown urine, muscle weakness, paralysis, breathing problems, skin blisters in sunlight)
- If you have symptoms of cutaneous porphyria (e.g., blisters, fragile skin, slow healing, infections, skin color changes, scarring, or pain/burning/stinging/tingling/redness/swelling in sunlight)
- If someone in your family has porphyria, to see if you have inherited the condition
Preparation and collection
For a stool test, you may be instructed to not eat meat or take any aspirin-containing medicines for three days prior. No special preparations are needed for blood or urine tests.
Blood: A health care professional will take a blood sample from a vein in your arm using a small needle. 24-hour urine: You will collect all your urine during a 24-hour period using a container and instructions from your provider or laboratory. Random urine: You can provide a sample at any time of day, often done in a provider's office or lab. Stool: You will collect a sample and place it in a special container; your provider will give instructions on how to prepare and send it to a lab.
Blood test: There is very little risk; you may have slight pain or bruising at the needle site, but most symptoms go away quickly. Urine and stool tests: There are no known risks.
Understanding results
Porphyria is a rare disease and is hard to diagnose. Many symptoms are similar to those of other, more common diseases. If high levels of porphyrin are found, your provider will probably order more tests to confirm a diagnosis and determine the type of porphyria. There is no cure, but the condition can be managed with lifestyle changes and/or medicines. Specific treatment depends on the type of porphyria.
- Normal porphyrin levels in blood, urine, or stool: No evidence of porphyria based on this test. Limitation: This test alone cannot rule out all forms of porphyria; clinical correlation is needed. Next step: Routine
- High porphyrin levels in blood, urine, or stool: May indicate porphyria. Further testing is needed to confirm the diagnosis and identify the type. Limitation: High levels can also be caused by other conditions; this test is not diagnostic by itself. Next step: Your provider will likely order additional tests to confirm and classify porphyria.
- Porphyria is rare and hard to diagnose; symptoms overlap with more common diseases.
- High porphyrin levels require confirmatory testing to establish a diagnosis.
- Reference intervals and interpretation should be provided by your healthcare professional.
What to do next
If you have questions about your results or about porphyria, talk to your provider.
- What type of porphyria do my results suggest?
- Do I need additional tests to confirm the diagnosis?
- What lifestyle changes or treatments might help manage my condition?