Porphyrin Tests

What are porphyrin tests?

Porphyrin tests measure the level of porphyrins in your blood, urine (pee), or stool (poop). Your body uses porphyrins to make heme. Heme is part of hemoglobin, which is a protein in your red blood cells that carries oxygen from your lungs to the rest of your body.

It's normal to have a small amount of porphyrins in your blood and other body fluids. But too much porphyrin may mean you have a type of porphyria. Porphyrias are a group of diseases that happen if you lack one of the proteins necessary to change porphyrins into heme. If your body doesn't use porphyrins correctly, they can build up and cause illness.

Porphyrias are very uncommon disorders that are usually inherited. That means these diseases tend to run in families because of a change in a gene that's passed down from parents to children.  There are two main groups of porphyrias:

• Acute porphyrias happen suddenly and usually last days or weeks. They mainly affect the nervous system. Sometimes they affect the skin, too.
• Cutaneous porphyrias are long-lasting and affect only the skin, causing blisters or pain when you are exposed to sunlight

There are eight types of porphyria that fall into either of these groups. Your symptoms and where excess porphyrins are in your body will help your health care provider determine a diagnosis of acute or cutaneous porphyria.

Other names: protoporphyrin; protoporphyrin, blood; protoporhyrin, stool; porphyrins, feces; uroporphyrin; porphyrins, urine; Mauzerall-Granick test; acid; ALA; porphobilinogen; PBG; free erythrocyte protoporphyrin; fractionated erythrocyte porphyrins; FEP

What are they used for?

Porphyrin tests are used to help diagnose or to monitor all types of porphyria.

Why do I need a porphyrin test?

You may need a porphyrin test if you have symptoms of porphyria. Each porphyria group has different symptoms:

Symptoms of acute porphyria may be mild or severe. Without early treatment, they may get worse and even become life-threatening. Symptoms may include:

• Pain in the abdomen (belly), back, or arms and legs
• Constipation
• Nausea and vomiting
• Mental changes, such as anxiety, confusion, and seizures
• Problems urinating (peeing), leaking urine, or red or brown urine
• Problems with nerves that control movement, which may cause muscle weakness, paralysis, and breathing problems
• Skin blisters when skin is in sunlight (for certain types of acute porphyria)

Symptoms of cutaneous porphyria happen when skin is exposed to sunlight.
Symptoms of some types of cutaneous porphyria include:

• Blisters
• Fragile skin that is easily wounded and slow to heal
• Infections in blisters or wounds
• Changes in skin color or scarring

Other types of cutaneous porphyria usually don't cause blisters. Instead, sunlight may cause these skin symptoms:

• Pain, burning, stinging, or tingling
• Redness
• Swelling

If someone in your family has porphyria, you may need a porphyrin test to see if you have inherited the condition. But the most common type of porphyria isn't inherited. It usually develops after age 30 and may be caused by conditions, such as:

• Hemochromatosis, a disease where too much iron builds up in the body
• Alcohol use disorder (AUD)
• Smoking
• Viral infections, such as hepatitis C and HIV
• Taking estrogen in medicines such as birth control pills or hormone replacement therapy

What happens during porphyrin testing?

Porphyrins can be tested in blood, urine, or stool. The most common types of porphyrin tests are listed below. The type of test your provider will use to diagnose you will depend on the type of porphyria they think you might have.

• Blood Test
  • A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.
• 24-Hour Urine Sample
  • You will collect all your urine during a 24-hour period. For this test, your provider or laboratory will give you a container and specific instructions on how to collect your samples at home. Be sure to follow all instructions carefully. This 24-hour urine sample test is used because the amounts of substances in urine, including porphyrin, can vary throughout the day. So, collecting several samples in a day may give a more accurate picture of your urine content.
• Random Urine Test
  • You can provide your sample at any time of day, with no special preparations or handling needed. This test is often done in your provider's office or a lab.
• Stool Test (also called protoporphyrin in stool)
  • You will collect a sample of your stool and place it in a special container. Your provider will give you instructions on how to prepare your sample and send it to a lab.

Will I need to do anything to prepare for the test?

You don't need any special preparations for blood or urine tests.

For a stool test, you may be instructed to not eat meat or take any aspirin-containing medicines for three days prior to your test.

Are there any risks to porphyrin tests?

There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

There are no known risks to urine or stool tests.

What do the results mean?

Porphyria is a rare disease and is hard to diagnose. Many of the symptoms of porphyria are similar to those of other, more common diseases.

If high levels of porphyrin are found in your blood, urine, or stool, your provider will probably order more tests to confirm a diagnosis and to find out what kind of porphyria you have.

While there is no cure for porphyria, the condition can be managed. Certain lifestyle changes and/or medicines can help prevent the symptoms and complications of the disease. Specific treatment depends on the type of porphyria you have. If you have questions about your results or about porphyria, talk to your provider.

Learn more about laboratory tests, reference ranges, and understanding results.

Is there anything else I need to know about porphyrin tests?

While most types of porphyria are inherited, other types of porphyria can also be acquired. Acquired porphyria can be caused by a variety of factors, including overexposure to lead, HIV, hepatitis C, excess iron intake, and/or heavy alcohol use.