WSLH Toxicology: Erythrocyte Protoporphyrin

Erythrocyte Protoporphyrin (EP) testing is performed on capillary and venous whole blood samples as an adjunct to blood lead testing. The EP test provides an indication of the extent and duration of lead exposure. Other common names for this test are free erythrocyte protoporphyrin (FEP) and zinc protoporphyrin (ZPP). EP was the primary screening tool for childhood lead poisoning, but has been replaced by the blood lead test due to its lack of sensitivity in detecting the low levels of lead exposure now of concern. The EP test is also a sensitive indicator of iron deficiency anemia.

Specimen collection:

100 µL of whole blood collected in evacuated tubes or microcontainers with EDTA or heparin anticoagulant. EP testing can be performed on the same specimens submitted for blood lead testing.

Testing Procedure:

Protoporphyrin in whole blood is determined by extraction and spectrofluorometric measurement.

Links:

National Committee on Clinical Laboratory Standards (NCCLS) Erythrocyte Protoporphyrin Testing: Approved Guidelines