Protoporphyrins, Fractionation, Washed Erythrocytes
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
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
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.
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
It is essential to proceed expeditiously with obtaining, processing, and dispatching the specimen, precisely following procedures specified in Specimen Required, paying special heed to maintaining low temperatures.
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.
<20 mcg/dL packed cells
<60 mcg/dL packed cells
See The Heme Biosynthetic Pathway in Special Instructions.
Clinical References 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 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