What test measures toxic levels of lead affecting heme synthesis?

The Free Erythrocyte Protoporphyrin test (FEP) is specifically designed to assess the levels of protoporphyrin in red blood cells, which can be elevated in cases of lead toxicity. When lead is present in the body, it interferes with the normal synthesis of heme, the iron-containing component of hemoglobin. This disruption leads to an accumulation of protoporphyrin, as the body is unable to effectively convert it into heme.

In contrast, other tests mentioned do not specifically measure lead's impact on heme synthesis. A complete blood count provides a broad overview of blood components but does not focus on detecting heavy metal toxicity. The serum ferritin test assesses iron stores in the body, which is also not directly related to measuring lead levels or its effect on heme synthesis. Hemoglobin electrophoresis is utilized to identify different types of hemoglobin and diagnose hemoglobinopathies but does not give information regarding lead exposure or its interference in heme production.

Thus, the Free Erythrocyte Protoporphyrin test serves as a direct indicator of the impact of lead on heme synthesis and is particularly relevant in populations at risk of lead exposure.