Ordering Guidance

This test is for diagnosis of acute intermittent porphyria. Porphobilinogen deaminase, also known as hydroxymethylbilane synthase and uroporphyrinogen I synthase, is commonly confused with uroporphyrinogen III synthase, the enzyme deficient in congenital erythropoietic porphyria.

Necessary Information

1. Patient’s age is required

2. Include a list of medications the patient is currently taking.

Specimen Required

Patient Preparation: For 24 hours before specimen collection, patient must not consume any alcohol. This is essential as ethanol induces porphobilinogen deaminase activity, which may lead to a false-normal result.

Container/Tube:

Preferred: Green top (sodium heparin)

Acceptable: Lavender top (EDTA) or green top (lithium heparin)

Specimen Volume: 4 mL; full tube

Collection Instructions: Refrigerate specimen as soon as possible.