Clinical significanceClinical indicationsSample typePreparationNotes
Clinical significance
Lead interferes with haem synthesis by blocking the enzyme haem synthetase (ferrochelatase), causing an increase in protoporphyrin IX, which ends up combining with zinc ions, for which it has a strong affinity, forming zinc protoporphyrin.
Clinical indications
Occupational exposure to lead.
Sample type
The patient must have a blood sample taken
Preparation
Fasting is not required
Notes
Zinc protoporphyrin is a better marker of lead poisoning than blood lead itself; moreover, the rise in zinc protoporphyrin persists for a long time even after exposure to the metal has stopped.