Protoporphyrin (Blood)

Does this test have other names?

Protoporphyrin, ZPP, zinc protoporphyrin test, erythrocyte protoporphyrin test

What is this test?

The protoporphyrin test is used to diagnose blood problems caused by lead. The test can show lead exposure or lead poisoning. Lead poisoning is extremely dangerous because lead can damage organs throughout the body.

Lead poisoning does not always cause symptoms, so a blood test may be the only way to confirm lead exposure or poisoning. (Healthcare providers usually order a protoporphyrin test after a simple blood screening shows higher levels of lead.) The test can also find an iron deficiency anemia or other types of anemia.

The protoporphyrin test doesn't measure the levels of lead in the blood. Instead it measures how the blood has been affected by lead. Lead can harm the blood's ability to make new blood cells. The protoporphyrin test measures the effects of lead exposure that have happened over the past 2 to 3 months. 

Why do I need this test?

You may need this test if you have signs and symptoms of iron deficiency or lead poisoning. These include:

• Repeated miscarriages or fertility problems

• Digestive problems such as nausea, vomiting, or constipation

• High blood pressure

• Fatigue

• Weakness

• Hearing problems

• Headaches

• Difficulty concentrating

• Seizures

• Nerve damage

• Anemia

• Metallic taste in the mouth

You may need this test if the result from your blood lead screening is 25 micrograms per deciliter (mcg/dL) or higher. Children may have the protoporphyrin test to confirm lead poisoning. You may need this test if you have been exposed to lead or if your healthcare provider suspects that you have lead poisoning or an iron deficiency. It is important to find out if you have toxic levels of lead in your body, because the results can be permanent.

What other tests might I have along with this test?

You may need a number of other tests along with a protoporphyrin test, including:

• Complete blood count

• Blood erythrocyte protoporphyrin test

• Reticulocyte count, or a count of young red blood cells

• Serum iron, iron binding capacity, ferritin levels, or other measurements of iron in the blood

• X-rays 

What do my test results mean?

Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your healthcare provider.

Test results showing zinc protoporphyrin levels higher than 50 mcg/dL mean that you have a high level of lead in your blood.

How is this test done?

The test requires a blood sample, which is drawn through a needle from a vein in your arm. 

Does this test pose any risks?

The risks are very minor. The finger prick or needle may feel uncomfortable or painful. You may experience bruising, soreness, or pain in your hand or arm at the puncture spot. These symptoms usually go away soon after the test is over.

What might affect my test results?

Only exposure to lead should affect your test results. If a fingerstick method is used, contamination of your fingertip can affect the results. If you have a positive result, it should be confirmed before you start treatment.

How do I get ready for this test?

A blood test rarely requires any preparation. You can probably eat, drink, and take your medicine as usual, but check with your healthcare provider to be sure. Remember to tell your provider about any medicines or supplements that you take. Your provider will also tell you if you need to skip any of your regular medicines before the test.