Porphyrins, Blood and Urine

General

Synonym/Acronym:
Blood: Erythrocyte protoporphyrin, EP, free erythrocyte protoporphyrin, FEP; and Urine: Coproporphyrin, porphobilinogen, urobilinogen, and other porphyrins.

Rationale
To assist in diagnosing acquired and inherited conditions associated with porphyrias, such as anemias related to chronic disease, hemolysis, iron deficiency, and heavy metal toxicity.

Patient Preparation
There are no food, fluid, activity, or medication restrictions unless by medical direction. Usually, a 24-hr urine collection is ordered for urine testing. As appropriate, provide the required urine collection container and specimen collection instructions.

Normal Findings
Method: Blood: Fluorometry for erythrocyte protoporphyrin; Urine: High-performance liquid chromatography for porphyrins; spectrophotometry for porphobilinogen.


Blood Study—Erythrocyte Protoporphyrin (EP)
Conventional UnitsSI Units (Conventional Units × 0.0178)
Adult
Male
  Less than 30 mcg/dLLess than 0.534 micromol/L
Female
  Less than 40 mcg/dLLess than 0.712 micromol/L

Urine
TestUnits
Coproporphyrins
  Male0–230 nmol/24 hr
  Female0–170 nmol/24 hr
Hexacarboxylporphyrin0–8 nmol/24 hr
Heptacarboxylporphyrin0–9 nmol/24 hr
Uroporphyrins0–30 nmol/24 hr
Porphobilinogen0–2 mg/24 hr

Critical Findings and Potential Interventions
N/A

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