Ordering Recommendation

Screen for erythropoietic protoporphyria (EPP) in patients with cutaneous photosensitivity.

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation

Royal blue (EDTA), lavender (EDTA), pink (K2EDTA), or Tan ( K2EDTA). Use royal blue tube when also testing for lead. 

Specimen Preparation

Protect from light during collection, storage, and shipment. Transfer 1 mL whole blood to an ARUP Amber Transport Tube. (Min: 0.5 mL)

Storage/Transport Temperature


Unacceptable Conditions

Specimens not collected in EDTA. Clotted specimens.


Specimen should be tested for lead FIRST to avoid potential contamination problems. Specimens not protected from light acceptable with a disclaimer.


Ambient: Unacceptable; Refrigerated: 2 weeks; Frozen: 1 month




Mon, Wed, Sat


1-4 days

Reference Interval

0-35 µg/dL

Interpretive Data

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Compliance Category

Laboratory Developed Test (LDT)


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 µg/dL).  Elevated protoporphyrin (as in erythropoietic protoporphyria) and zinc coproporphyrin (usually associated with childbirth) can increase the apparent EP signal. A more specific test for free protoporphyrin is Porphyrins, Serum Total (0080429).  Specimens which are hemolyzed, clotted, or improperly aliquoted may show false elevations.

Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
0020607 Erythrocyte Porphyrin (EP) 2898-5
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • FEP
  • Free Erythrocyte Porphyrin
  • Porphyrins (FEP)
  • Protoporphyrin, Free Erythrocyte (FEP)
  • Protoporphyrins, Total, Erythrocytes
  • RBC Porphyrins
  • Red Blood Cell Porphyrins
Erythrocyte Porphyrin (EP), Whole Blood