Test ID: PTP
Porphyrins, Total, Plasma
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
Differential diagnosis of porphyrias
Differential diagnosis of photosensitive skin manifestations
Determining whether skin problems are related to an accumulation of porphyrins (renal failure porphyria, porphyria cutanea tarda, congenital erythropoietic porphyria, and erythropoietic protoporphyria) or some other problem
Genetics Test Information Provides information that may help with selection of the correct test or proper submission of the test request
Plasma specimens from patients with active porphyria cutanea tarda (PCT), congenital erythropoietic porphyria (CEP), and erythropoietic protoporphyria (EPP) may exhibit increased plasma porphyrin levels. However, a definitive diagnosis cannot be made by plasma analysis alone.
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 |
|---|---|---|---|
| PFP | Porphyrins, Fractionation, P | No | No |
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
If total porphyrins are >1.0 mcg/dL, then PFP/8733 Porphyrins, Fractionation, Plasma will be performed at an additional charge.
The following algorithms are available in Special Instructions:
-Porphyria (Acute) Testing Algorithm
-Porphyria (Cutaneous) Testing Algorithm
-The Heme Biosynthetic Pathway
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
PTP/8731: Extraction and Scanning Spectrofluorometry
PFP/8733: 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
Congenital Erythropoietic Porphyria (CEP)
Coproporphyrin
EPP (Erythropoietic Protoporphyria)
Erythropoietic Protoporphyria (EPP)
PCT (Porphyria Cutanea Tarda)
Porphyria Cutanea Tarda (PCT)
Protoporphyrin
Uroporphyrin
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.
Collection Container/Tube:
Preferred: Green top (heparin)
Acceptable: Lavender top (EDTA)
Submission Container/Tube: Amber vial (Supply T192)
Specimen Volume: 3 mL
Collection Instructions:
1. Patient should abstain from alcohol for at least 24 hours prior to specimen collection.
2. Send specimen in amber vial to protect from light.
Additional Information: Include a list of medications the patient is currently taking.
Forms:
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. 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 OK; Gross OK |
| Lipemia | Mild OK; Gross OK |
| Icterus | Mild OK; Gross OK |
| Other | Plasma gel tube or specimen not protected from light |
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 |
|---|---|---|
| Plasma | Frozen | 7 days |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
The porphyrias are a group of inborn errors of metabolism resulting from defects in the heme biosynthetic pathway. Enzymatic deficiencies result in the accumulation and excretion of intermediary metabolites in different specimen types. The pattern of excretion of the heme precursors in urine and feces and the accumulation within erythrocytes allow for the detection and differentiation of the hereditary porphyrias. These accumulations cause characteristic clinical manifestations, which may include neurologic and psychological symptoms and cutaneous photosensitivity, depending upon the specific disorder. Although genetic in nature, environmental factors may exacerbate symptoms, significantly impacting the severity and course of disease. Early diagnosis coupled with education and counseling of the patient regarding the disease and treatment including avoidance of precipitating factors are important for successful management.
Historically, the porphyrias have been divided into 2 groups, erythropoietic and hepatic based on the major site of substrate accumulation and/or overproduction. Another classification is based on clinical presentation and divides the porphyrias into acute or nonacute (cutaneous) categories. The acute porphyrias include acute intermittent porphyria (AIP), hereditary coproporphyria (HCP), and variegate porphyria (VP). The nonacute porphyrias include congenital erythropoietic porphyria (CEP), porphyria cutanea tarda (PCT), and erythropoietic protoporphyria (EPP).
PCT is the most common form of porphyria. It presents clinically with increased skin fragility and the formation of vesicles and bullae on sun-exposed areas of the skin. PCT can be either sporadic (acquired) or inherited in an autosomal dominant manner. A biochemical diagnosis of PCT is characterized by increased urinary excretion of uroporphyrin and heptacarboxylporphyrin. Lesser amounts of hexacarboxylporphyrin, pentacarboxylporphyrin, and coproporphyrin may also be excreted. Hepatoerythropoietic porphyria (HEP) is observed when an individual inherits PCT from both parents. Patients exhibit a similar porphyrin excretion pattern as PCT, although the clinical presentation is similar to what is seen in CEP.
The clinical features of the acute porphyrias include abdominal pain, sensory neuropathy, and psychosis. Photosensitivity is not associated with acute intermittent porphyria (AIP), but may be present in HCP and VP. The biochemical diagnosis of AIP is based upon an increased urinary excretion of porphobilinogen (PBG) and aminolevulinic acid (ALA). In addition, uroporphyrin is also usually increased. A urine specimen obtained during an acute episode is most informative, as these analytes may be normal or only slightly increased between acute episodes of AIP. With respect to HCP and VP, the excretion pattern observed in urine is indistinguishable from one another with elevations of both coproporphyrin and PBG excretion being observed in urine. Fecal porphyrins analysis is recommended to differentiate VP from HCP.
CEP is a rare disorder typically presenting in childhood with prominent photosensitivity and voiding of dark, wine-colored urine. A few milder adult-onset cases have been documented as well as cases that are secondary to myeloid malignancies. A biochemical diagnosis of CEP is characterized by increased urinary excretion of uroporphyrin and coproporphyrin with the excretion of uroporphyrin usually exceeding that of coproporphyrin and the series I isomers predominating. Lesser amounts of the heptacarboxyl-, hexacarboxyl-, and pentacarboxyl porphyrins may be excreted. The urinary excretion of ALA and PBG is usually within normal limits.
Typically, the work up of patients with a suspected porphyria is most effective when following a stepwise approach. See Porphyria (Acute) Testing Algorithm and Porphyria (Cutaneous) Testing Algorithm in Special Instructions, or contact Mayo Medical Laboratories to discuss testing strategies. Refer to The Challenges of Testing For and Diagnosing Porphyrias, Mayo Medical Laboratories Communique 2002 Nov;27(11) for more information.
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.
< or =1.0 mcg/dL
Interpretation Provides information to assist in interpretation of the test results
A mild elevation of total plasma porphyrins is an expression of a primary (eg, active porphyria cutanea tarda, congenital erythropoietic porphyria, erythropoietic protoporphyria, variegate porphyria, or hereditary coproporphyria) or secondary defect in the biosynthesis of heme. However, the specific type of porphyria cannot be determined by total plasma porphyrin analysis alone.
| Porphyria | Biochemical abnormalities |
| Acute intermittent porphyria | Typically normal. May see increased uroporphyrin. |
| Congenital erythropoietic porphyria | Increased uroporphyrin and coproporphyrin; if isomers performed, series I isomers. |
| Porphyria cutanea tarda | Increased uroporphyrin and heptacarboxyl porphyrin with lesser increases of hexa-, penta- and coproporphyrin. |
| Hereditary coproporphyria | Typically normal. May see increased coproporphyrin. |
| Variegate porphyria | Typically normal. May see increased coproporphyrin and/or protoporphyrin with other dicarboxyl porphyrins (peaks between coproporphyrin and protoporphyrin). |
| Erythropoietic protoporphyria | Increased protoporphyrin. |
When abnormal results are detected, a detailed interpretation is provided, which may include:
-An overview of the results and of their significance
-Elements of differential diagnosis
-Recommendations for additional biochemical testing (ie, enzyme assays)
-Phone number to reach 1 of the laboratory directors in case the referring physician has additional questions
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Plasma porphyrins are extremely sensitive to light and may degrade to normal levels if not handled properly. Send specimen frozen in amber vial (Supply T192) to protect from light.
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-Porphyrins, total
82492-Porphyrins, fractionation (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 |
|---|---|---|
| 8731 | Porphyrins, Total, P | 2815-9 |
| 34252 | Reviewed By | N/A |
| 33869 | Interpretation | 59462-2 |
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