The ZPP blood test measures the amount of zinc protoporphyrin that is present. There are two primary reasons why this test is ordered.
1. To determine if there has been lead exposure in adults.
2. To determine if there is an iron deficiency in children.
Red blood cells generally contain a small amount of ZPP. Most of the protoporphyrin will combine with iron that is present to form a building block of hemoglobin so that oxygen can be carried throughout the body. When there isn’t enough iron, then the protoporphyrin will bind to zinc instead of iron.
There are two tests that can be ordered with the ZPP blood test is requested. The FEP test, which measures free erythrocite protoporphyrin measures ZPP and the protoporphyrin that is not bound to zinc. The ZPP/heme ratio will tell a doctor how much of the protoporphyrin is binding to iron so that hemoglobin can form.
OSHA Mandates ZPP Blood Tests For Certain Occupations
OSHA mandates that employees receive regular ZPP blood tests when they are working in industrial settings. Every time a lead level is ordered, OSHA strongly recommends that this blood test be part of the procedure. Lead poisoning can happen by inhaling lead-contaminated dust, handling lead, or having lead on the foods that are eaten because of residual lead on the hands or body. The ZPP test is necessary because it measures long-term average exposures of 3-4 months past instead of acute exposures and it will not change immediately when the lead is removed.
The testing methods for ZPP in adults are not sensitive enough to measure lead poisoning in children. This is why the blood test is used to determine if there is an iron deficiency present instead. This can be determined if there is a low ratio of heme compared to the protoporphyrin levels that are present.
When To See a Doctor About the ZPP Blood Test
For adults that suspect lead poisoning or exposure, certain symptoms may require a visit to the doctor to have the ZPP blood test ordered. Weakness, memory loss, high blood pressure, and unexplained tingling in the feet or hands can all be indications that lead is present within the body. Certain hobbies, such as creating stained glass, also bring about higher risks of lead exposure, so tests may be ordered for these individuals as well.
For children that may be suffering from an iron deficiency, the symptoms may include a chronic feeling of tiredness, weakness, headache complaints, and dizziness. Anemia may also cause chest pains, leg pains, and a severe feeling of not being able to breathe.
ZPP levels are considered normal when they are very low. Increased levels of ZPP indicate the normal heme production has been disrupted in an unknown way.
ZPP May Also Be Positive For Other Factors
Lead poisoning and iron deficiency might be the two most common reasons for increased levels of ZPP, but there are other circumstances that can cause a positive result. Inflammatory conditions can cause increased levels of ZPP, as can the presence of an infection. If anemia is present because of a chronic disease instead of an iron deficiency, then the ZPP blood test will also be positive. Very high levels are often indicators that Porphyria is present, which is a disorder that causes a person’s skin to be extremely sensitive to sunlight.
Most people do not this blood test as an adult. Only those who work around lead or have a hobby that exposes them to lead will typically have this blood test ordered. Children who are suspected to have an iron deficiency will have this test ordered, but most children will not.
What Needs To Be Done To Prepare For the Test?
No actions need to be taken for the ZPP blood test. It can be taken the day that it is ordered by a doctor. It is important to remember that a recent exposure to lead will not be measured by this test. It will only show an average exposure level over the last 90-120 days. The blood can be drawn from a vein in the arm or taken from a fingerstick, which is usually the preferred method for testing children.
Positive results do not necessarily mean lead poisoning is present or that there is an iron deficiency. It does mean that there is something going on within the body that needs to be addressed. Speak with your doctor about your dietary habits and medications/supplements before having the test completed so accurate results can be achieved. In doing so, you will be able to get the answers that you need to maintain your good health.