Protoporphyrin, Free Erythrocyte, and Zinc Protoporphyrin
| Protoporphyrin, Free Erythrocyte, and Zinc Protoporphyrin | | | |
| Number | | 010165 |
| CPT | | 84202 |
| Related Information | | Lead and Protoporphyrin (FEP/ZPP), Blood (Pediatric) Lead, Blood (Adult) Lead Standard Profile, Blood |
| Synonyms | | FEP ; ZPP |
| Test Includes | | Zinc protoporphyrin and free erythrocyte protoporphyrin |
| Specimen | | Whole blood |
| Volume | | 7 mL |
| Minimum Volume | | 0.2 mL |
| Container | | Lavender-top (EDTA) Vacutainer® tube, Microtainer™ (EDTA) tube, or royal blue-top (EDTA or heparin) tube; submit original tube. |
| Collection | | Mix tube thoroughly to avoid clotting. |
| Storage Instructions | | Maintain specimen at room temperature. |
| Causes for Rejection | | Clotted specimen |
| Reference Interval | | - FEP, blood: environmental exposure: adults: 0-34 μg/dL
- ZPP, blood: environmental exposure: adults: 0-38 μg/dL; occupational exposure: BEI® (sampling time is after 1 month's exposure): 100 μg/dL1
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| Use | | Monitor chronic industrial exposure to lead |
| Limitations | | Fluorescent substances in plasma may interfere with hematofluorometer results.2 Skin contamination may lead to false elevations. Both this test and blood lead are needed for full evaluation. |
| Methodology | | Fluorometry |
| Additional Information | | “Free” protoporphyrin is noncomplexed, nonheme protoporphyrin. Lead poisoning is also characterized by elevated plasma and urine delta aminolevulinic acid and increased urinary coproporphyrin. Urinary porphobilinogen and uroporphyrin are normal to slightly increased.3 Free erythrocyte protoporphyrin is a sensitive test for lead toxicity or chronic exposure in adults. Erythrocyte protoporphyrin levels should not be used as a screening test for lead poisoning in children.4 The diagnosis of lead exposure or poisoning includes consideration of environmental exposure, as well as symptoms and abnormal erythrocyte protoporphyrin. Increased lead absorption is reported in the presence of iron deficiency.5 |
| Footnotes | | - BEI® (Biological Exposure Indices) based on 1994-1995 Recommendations of the American Conference of Governmental Industrial Hygienists (ACGIH).
- Marsh WL Jr, Nelson DP, and Koenig HM, “Free Erythrocyte Protoporphyrin (FEP) I. Normal Values for Adults and Evaluation of the Hematofluorometer,” Am J Clin Pathol, 1983, 79(6):655-60.
- Chisholm JJ, “Increased Lead Absorption and Lead Poisoning,” Nelson Textbook of Pediatrics, 13th ed, Behrman RE, Vaughan VC III, and Nelson WE, eds, Philadelphia, PA: WB Saunders Co, 1987, 1507-11.
- DeBaun MR and Sox HC Jr, “Setting the Optimal Erythrocyte Protoporphyrin Screening Decision Threshold for Lead Poisoning: A Decision Analytic Approach,” Pediatrics, 1991, 88(1):121-31.
- Carraccio CL, Bergman GE, and Daley BP, “Combined Iron Deficiency and Lead Poisoning in Children. Effect on FEP Levels,” Clin Pediatr (Phila), 1987, 26(12):644-7
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| References | | Bird TD, Wallace DM, and Labbe RF, “The Porphyria, Plumbism, Pottery Puzzle,” JAMA, 1982, 247(6):813-4. Schreiber WE, “Iron, Porphyrin and Bilirubin Metabolism,” Clinical Chemistry - Theory, Analysis, and Correlation, 2nd ed, Kaplan LA and Pesce AJ, eds, St Louis, MO: Mosby-Year Book Inc, 1989, 496-511. Zanella A, Gridelli L, Berzuini A, et al, “Sensitivity and Predictive Value of Serum Ferritin and Free Erythrocyte Protoporphyrin for Iron Deficiency,” J Lab Clin Med, 1989, 113(1):73-8. |
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