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Test ID: PPFE    
Protoporphyrins, Fractionation, Whole Blood

Useful For Suggests clinical disorders or settings where the test may be helpful

Establishing a biochemical diagnosis of erythropoietic protoporphyria

 

Differential diagnosis of chronic intoxication from exposure to a variety of causes including heavy metals and chemicals

 

Differential diagnosis in some cases of iron-deficiency anemia

 

There are 2 test options: whole blood (PPFE/8739 Protoporphyrins, Fractionation, Whole Blood) and washed RBCs (PPFWE/31891 Protoporphyrins, Fractionation, Washed Erythrocytes). The whole blood option is easiest for clients but requires that the specimen arrive at Mayo Medical Laboratories within 72 hours of draw. When this cannot be ensured, washed RBCs should be submitted.

Genetics Test Information Provides information that may help with selection of the correct test or proper submission of the test request

Includes separate quantitation of zinc protoporphyrin and free protoporphyrin. Abstinence from alcohol is essential for at least 24 hours as alcohol suppresses enzyme activity, potentially leading to falsely increased results.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Zinc-complexed protoporphyrin can be increased in erythrocytes in association with:

-Iron deficiency anemia (the most common cause of elevated zinc protoporphyrin)

-Chronic intoxication by heavy metals (ie, lead) or various organic chemicals

-Hepatoerythropoietic porphyria

 

Noncomplexed (free) protoporphyrin is increased disproportionately in erythrocytes in cases of erythropoietic protoporphyria.

 

The following algorithms are available in Special Instructions:

-Porphyria (Acute) Testing Algorithm

-Porphyria (Cutaneous) Testing Algorithm

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

FREE PROTOPORPHYRIN

<20 mcg/dL packed cells

 

ZINC-COMPLEXED PROTOPORPHYRIN

<60 mcg/dL packed cells

See The Heme Biosynthetic Pathway in Special Instructions.

Interpretation Provides information to assist in interpretation of the test results

Values of zinc-complexed protoporphyrin >60 mcg/dL suggest iron deficiency anemia or may indicate chronic intoxication by heavy metals or organic chemicals.

 

A predominance of noncomplexed (free) protoporphyrin indicates a diagnosis of erythropoietic protoporphyria.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Abstinence from alcohol is essential for at least 24 hours as alcohol suppresses enzyme activity, potentially leading to false-negative results.

 

It is essential to proceed expeditiously with obtaining, processing, and dispatching the specimen, precisely following the procedures specified in Specimen Required, paying special heed to maintaining low temperatures.

Clinical Reference Provides recommendations for further in-depth reading of a clinical nature

1. Ellefson RD: Porphyrinogens, porphyrins, and the porphyrias. Mayo Clin Proc 1982;57:454-458

2. Nuttall KL, Klee GG: Analytes of hemoglobin metabolism-porphyrins, iron, and bilirubin. In Tietz Fundamentals of Clinical Chemistry. Fifth edition. Edited by CA Burtis, ER Ashwood. Philadelphia, WB Saunders Book Company, 2001, pp 584-607

3. Anderson KE, Sassa S, Bishop DF, Desnick RJ: Disorders of heme biosynthesis: X-linked sideroblastic anemia and the porphyrias. In The Metabolic Basis of Inherited Disease. Eighth edition. Edited by CR Scriver, AL Beaudet, WS Sly, et al. New York, McGraw-Hill Medical Publishing Division, 2001, pp 2991-3062

4. Whatley SD, Ducamp S, Gouya L, et al: C-terminal in the ALAS2  gene lead to gain of function and cause X-linked dominant protoporphyria without anemia or iron overload. Am J Hum Genet 2008 Sep;83(3):408-414

Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test