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Test Code
ERPO
Test Name
Erythrocyte Porphyrin (EP), Whole Blood
CPT Codes
84202
Expected Turnaround Time
1 - 4 days
Clinical Utility
Screen for erythropoietic protoporphyria (EPP) in patients with cutaneous photosensitivity.
Specimen and Container Info

Specimen Type: Whole Blood

Collection Container: Royal Blue (EDTA)

Alternate Collection Container: Lavender Top (EDTA) or Pink Top (EDTA)

Desired Specimen Volume: 1 mL
Collection Instructions
  1. Collect a royal blue top (EDTA) tube via venipuncture.
    1. Use a royal blue tube when also testing for lead.
  2. Protect from light during collection, storage, and shipment.
Processing and Submission Instructions
  1. Transfer 1 mL of whole blood to an amber aliquot tube (screw cap).
  2. If an amber aliquot tube is not available, cover sample completely with aluminum foil.
Patient Preparation

Specimen should be tested for lead FIRST to avoid potential contamination problems.
Transport Instructions

Transport to the laboratory refrigerated. 
Stability Requirements

Refrigerated

14 days

Frozen

1 month
Causes for Rejection
  • Clotted specimens
Methodology
Fluorometry
Reference Intervals

See patient report.
Limitations

Elevated EP results are seen in early and late iron deficiency, in the anemia of chronic disease, and in chronic lead poisoning (typically when blood lead is greater than 25 ug/dL). Elevated protoporphyrin (as in erythropoietic protoporphyria) and zinc coproporphyrin (usually associated with childbirth) can increase the apparent EP signal.

Specimens which are hemolyzed, clotted, or improperly aliquoted may show false elevations.
Reference Lab
ARUP Laboratories
Testing Schedule
Routine, 3 times per week
The American Medical Association (AMA) Current Procedural Terminology (CPT) codes published by HNL Lab Medicine are guidelines and are intended for informational purposes only. CPT coding is the exclusive responsibility of the billing entity. View the Terms.
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