Test ID: PEE
Porphyrins Evaluation, Whole Blood
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Diagnosis of erythropoietic protoporphyria and congenital erythropoietic porphyria
Evaluation of chronic intoxication from exposure to a variety of agents including heavy metals and chemicals
Differentiating iron-deficiency anemia from other causes of elevated porphyrin levels
There are 2 test options: PEE/88886 Porphyrins Evaluation, Whole Blood and PEWE/31893 Porphyrins Evaluation, Washed Erythrocytes. The whole blood option is easiest for clients but requires that the specimen arrive at Mayo Medical Laboratories within 48 hours of draw. When this cannot be ensured, washed RBCs should be submitted.
Reflex Tests Lists test(s) that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial test(s)
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| PFR | Porphyrins, Fractionation | No | No |
| PPFR | Protoporphyrins, Fractionation | Yes, (order #8739) | No |
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
Testing begins with total RBC porphyrins. If the result is <80 mcg/dL, it is normal and testing is complete. If the total RBC porphyrin value is >80 mcg/dL, fractionation assays will be performed at an additional charge to identify the porphyrin involved. The protoporphyrin fractionation yields free protoporphyrin and zinc-complexed protoporphyrin. Depending on this result, porphyrins fractionation may be added, which fractionates and individually quantitates RBC porphyrins (uroporphyrin, coproporphyrin, and protoporphyrin).
The following algorithms are available in Special Instructions:
-Porphyria (Acute) Testing Algorithm
-Porphyria (Cutaneous) Testing Algorithm
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
Method Name A short description of the method used to perform the test
PEE/88886: Spectrofluorometric
PPFR/28116, PFR/28117: High-Performance Liquid Chromatography (HPLC)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Erythrocyte Porphyrin
Erythropoietic Protoporphyria (EPP)
Free Erythrocyte Porphyrin (FEP)
Heptacarboxyl Porphyrin
Pentacarboxyl Porphyrin
Protoporphyrin
Protoporphyrins, Total, Erythrocytes
RBC Porphyrins
Red Blood Cell Porphyrins
Uroporphyrin
Hexacarboxyl Porphyrin
Congenital Erythropoietic Porphyria (CEP)
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
All porphyrin tests on whole blood can be performed on 1 draw tube.
Specimen must arrive within 72 hours of draw. If specimen cannot arrive within 72 hours, order PEWE/31893 Porphyrins Evaluation, Washed Erythrocytes.
Container/Tube:
Preferred: Green top (sodium heparin)
Acceptable: Metal free, lavender top (EDTA) or green top (lithium heparin)
Specimen Volume: Full tube
Collection Instructions:
1. Patient should abstain from alcohol for 24 hours.
2. Immediately place specimen on wet ice.
Additional Information: Include a list of medications the patient is currently taking.
Forms:
1. 1. New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (Supply T576) is available in Special Instructions.
2. 2. If not ordering electronically, submit a Biochemical Genetics Request Form (Supply T439) with the specimen.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild reject; Gross reject |
| Lipemia | NA |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole blood | Refrigerated | 72 hours |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
The porphyrias are a group of inherited disorders resulting from an enzyme deficiency in the heme biosynthetic pathway. Depending on which enzyme is deficient, various porphyrins and their precursors accumulate in plasma, erythrocytes, and tissues, and are excreted in the urine, feces, or both.
The porphyrias can be classified as either erythropoietic or hepatic. Both the erythropoietic porphyrias and the chronic hepatic porphyrias are associated with cutaneous photosensitivity, but not with the neurological symptoms that accompany the acute hepatic porphyrias. Diagnosis of the erythropoietic porphyrias (ie, erythropoietic protoporphyria [EPP] and congenital erythropoietic porphyria [CEP]) can be determined by analysis of porphyrins in the erythrocytes.
Erythrocyte (RBC) porphyrins consist almost entirely of protoporphyrin. Increased RBC protoporphyrin is characteristic of EPP and of the intoxication porphyrias that may be caused by heavy metals, halogenated solvents, some pesticides, and medications. However, iron deficiency anemia is the most common cause of increased RBC protoporphyrin. Therefore, when total RBC porphyrins are elevated, fractionation and quantitation of zinc-complexed and noncomplexed (free) protoporphyrin are necessary to differentiate the inherited porphyrias from other causes of elevated porphyrin levels.
Zinc-complexed protoporphyrin may be increased in RBCs in association with:
-Iron-deficiency anemia (the most common cause of elevated zinc protoporphyrin)
-Chronic intoxication by heavy metals (primarily lead) or various organic chemicals
-CEP
-Hepatoerythropoietic porphyria, a rare form of porphyria caused by homozygous or compound heterozygous mutations in the uroporphyrinogen decarboxylase gene (UROD)
-X-linked dominant protoporphyria, a form of protoporphyria caused by a gain of function mutation in the C-terminal end of ALAS2 gene
Free protoporphyrin is increased in RBCs in association with EPP, an erythropoietic porphyria that is inherited in an autosomal dominant fashion. EPP is considered to be the third most common form of porphyria. It is caused by diminished ferrochelatase activity, which results in increased free protoporphyrin levels in RBCs, plasma, and feces. Onset of symptoms typically occurs in childhood with cutaneous photosensitivity in sun-exposed areas of the skin, generally becoming worse in the spring and summer months. Common symptoms may include itching, edema, erythema, stinging or burning sensations, and occasionally scarring of the skin in sun-exposed areas.
CEP is an erythropoietic porphyria that is inherited in an autosomal recessive fashion. CEP is caused by uroporphyrinogen III synthase deficiency, which results in the accumulation and excretion of uroporphyrin I and coproporphyrin I in urine and feces. Circulating RBCs contain measurable amounts of uroporphyrin and coproporphyrin. RBC zinc protoporphyrin may also be elevated due to increased erythropoiesis. Symptoms typically present in early infancy with red-brown staining of diapers, severe cutaneous photosensitivity with fluid-filled bullae and vesicles. Other common symptoms may include thickening of the skin, hypo- and hyperpigmentation, hypertrichosis, cutaneous scarring, and deformities of the fingers, eyelids, lips, nose, and ears.
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.
PORPHYRINS, TOTAL, RBC
<80 mcg/dL packed cells
FREE PROTOPORPHYRIN
<20 mcg/dL packed cells
ZINC-COMPLEXED PROTOPORPHYRIN
<60 mcg/dL packed cells
UROPORPHYRIN
< or =2 mcg/dL packed cells
HEPTACARBOXYLPORPHYRIN
< or =1 mcg/dL packed cells
HEXACARBOXYLPORPHYRIN
< or =1 mcg/dL packed cells
PENTACARBOXYLPORPHYRIN
< or =1 mcg/dL packed cells
COPROPORPHYRIN
< or =2 mcg/dL packed cells
PROTOPORPHYRIN
<80 mcg/dL packed cells
Interpretation Provides information to assist in interpretation of the test results
An elevation of total RBC porphyrins can be an expression of a primary or secondary defect in the biosynthesis of heme. However, the specific type of porphyria cannot be determined by total porphyrin analysis alone.
Total RBC porphyrin values >80 mcg/dL suggest the existence of an intoxication problem or a metabolic problem that involves accelerated erythropoiesis. If the total RBC porphyrin concentration is elevated, additional testing (fractionation assays) is required to identify and quantify the specific affected porphyrin. Increased total RBC porphyrin concentrations may be due to:
-Free protoporphyrin, the predominant form that is elevated in patients with erythropoietic protoporphyria
-Zinc protoporphyrin, elevated in patients with heavy metal intoxication or iron deficiency anemia
-Uroporphyrin and coproporphyrin, preferentially elevated in patients with congenital erythropoietic porphyria
A written interpretation is included with all reports. When abnormal results are detected, a detailed interpretation is given, including:
-An overview of the results and their significance
-Elements of a differential diagnosis
-Recommendations for additional biochemical testing
A normal RBC porphyrin evaluation does not rule out other forms of porphyria including porphyria cutanea tarda (PCT), acute intermittent porphyria (AIP), hereditary coproporphyria (HCP), and variegate porphyria (VP).
See The Heme Biosynthetic Pathway in Special Instructions.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Abstinence from alcohol for at least 24 hours prior to specimen collection is essential as ethanol induces some enzyme activity and suppresses other enzymes along the heme biosynthetic pathway.
It is essential to proceed expeditiously with obtaining, processing, and dispatching the specimen, paying special heed to maintaining low temperatures (see Specimen Required). Failure to adhere to these directions may result in analyte degradation, yielding false-negative values.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. 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
2. Ellefson RD: Porphyrinogens, porphyrins and the porphyrias. Mayo Clin Proc 1982;57:454-458
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 Published Division, 2001, pp 2991-3062
4. Sassa S: Modern diagnosis and management of the porphyrias. Br J Haematol 2006;135:281-292
5. Whatley SD, Ducamp S, Gouya B, et al: C-terminal deletions 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
Method Description Describes how the test is performed and provides a method-specific reference
This evaluation is performed as a 3-step analysis. First, the total RBC porphyrin concentration is determined by extracting the porphyrins from washed, resuspended RBCs using a mixture of ethyl acetate and acetic acid. The porphyrins are then back extracted into dilute hydrochloric acid. Total porphyrins are quantified using this extract via spectrofluorometry.(Piomelli S: Free erythrocyte porphyrins in the detection of undue absorption of Pb and Fe deficiency. Clin Chem 1977;23:264-269)
If the total porphyrin concentration is elevated, the RBCs are re-extracted using an acetone:water solution. This extraction allows for separation and quantification of zinc-complexed and noncomplexed (free) protoporphyrin via HPLC.(Ford RE, Ellefson RD: Quantitation of erythrocyte protoporphyrins and zinc protoporphyrin by high-pressure liquid chromatography. Clin Chem 1984;30:972)
Depending on the results from the acetone:water extraction, the original acid extract may be submitted for HPLC analysis to separate and quantitate the individual porphyrin analytes to aid in the diagnosis of congenital erythropoietic porphyria.(Ford RE, Ou C, Ellefson RD: Liquid chromatographic analysis for urinary porphyrins. Clin Chem 1981;27:397-401)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday; 8 a.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
84311-Spectrophotometry, analyte not elsewhere specified
82492-Chromatography, quantitative, column (eg, gas liquid or HPLC); multiple analytes, single stationary and mobile phase (if appropriate)
84202-Protoporphyrin, RBC; quantitative (if appropriate)
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| 88886 | Total Porphyrins, WB | 2814-2 |
| 29356 | Interpretation | 59462-2 |
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