Porphyrins, Quantitative, Random, Urine
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Preferred test during symptomatic periods for acute intermittent porphyria, hereditary coproporphyria, and variegate porphyria
Preferred test to begin assessment for congenital erythropoietic porphyria and porphyria cutanea tarda
Genetics Test Information Provides information that may help with selection of the correct test or proper submission of the test request
Preferred test during symptomatic periods for acute intermittent porphyria (AIP), hereditary coproporphyria (HCP), and variegate porphyria (VP). Preferred test to begin assessment for congenital erythropoietic porphyria (CEP) and porphyria cutanea tarda (PCT).
Testing includes porphobilinogen.
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
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
High-Performance Liquid Chromatography (HPLC) with Fluorometric Detection
Includes quantitation of coproporphyrins, uroporphyrins, and intermediate porphyrins (heptacarboxyl, hexacarboxyl, and pentacarboxyl). Includes liquid chromatography-tandem mass spectrometry (LC-MS/MS) determination of porphobilinogen.
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Porphyrins, QN, Random, U
Acute Intermittent Porphyria (AIP)
Congenital Erythropoietic Porphyria (CEP)
Hereditary Coproporphyria (HCP)
Porphyria Cutanea Tarda (PCT)
Variegate Porphyria (VP)
Congenital Erythropoietic Porphyria (CEP)
Hereditary Coproporphyria (HCP)
Porphyria Cutanea Tarda (PCT)
Variegate Porphyria (VP)
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.
Container/Tube: Amber, 60-mL urine bottle (Supply T596)
Specimen Volume: 20-50 mL
1. Patient should abstain from alcohol for 24 hours prior to collection.
2. Collect a random urine specimen.
3. Protect specimen from light.
Additional Information: Include a list of medications the patient is currently taking.
Forms: 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.
Specimen not protected from light, pH <5.0
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
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/or 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.
Urinary porphyrin determination is helpful in the diagnosis of most porphyrias including congenital erythropoietic porphyria (CEP), porphyria cutanea tarda (PCT), acute intermittent porphyria (AIP), hereditary coproporphyria (HCP), and variegate porphyria (VP). In addition, measurement of porphobilinogen (PBG) in urine is important in establishing the diagnosis of the acute neurologic porphyrias (AIP, HCP and VP). Neither urine porphyrins nor PBG is helpful in evaluating patients suspected of having erythropoietic protoporphyria (EPP).
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 AIP, HCP and VP. The nonacute porphyrias include CEP, PCT and 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 hexacarboxyl-, pentacarboxyl- 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 AIP but may be present in HCP and VP. The biochemical diagnosis of AIP is based upon an increased urinary excretion of 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.
In addition to being a sign of an inheritable problem, porphyrinuria may result from exposure to certain drugs and toxins or other medical conditions (ie, renal disease, hereditary tyrosinemia type I). Heavy metals, halogenated solvents, various drugs, insecticides, and herbicides can interfere with heme production and cause "intoxication porphyria." Chemically, the intoxication porphyrias are characterized by increased excretion of ALA, PBG, uroporphyrin and/or coproporphyrin in urine.
Typically, the workup 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 =30 nmol/L
< or =7 nmol/L
< or =2 nmol/L
< or =5 nmol/L
< or =110 nmol/L
< or =1.3 mcmol/L
See The Heme Biosynthetic Pathway in Special Instructions.
Abnormal results are reported with a detailed interpretation including an overview of the results and their significance, a correlation to available clinical information provided with the specimen, differential diagnosis, and recommendations for additional testing when indicated and available, and a phone number to reach one 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
Porphobilinogen (PBG) and porphyrins are susceptible to degradation at high temperature and exposure to light.
Ethanol and a variety of medications are known to interfere with heme synthesis leading to elevations in urine porphyrins, particularly coproporphyrin. Coproporphyrin elevation without concomitant PBG elevation should not be used as the basis for the diagnosis of porphyria, but may warrant follow-up testing with fecal porphyrin analysis.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Tortorelli S, Kloke K, Raymond K: Chapter 15: Disorders of porphyrin metabolism. In Biochemical and Molecular Basis of Pediatric Disease. Fourth edition. Edited by DJ Dietzen, MJ Bennett, ECC Wong. AACC Press, 2010, pp 307-324
2. Nuttall KL, Klee GG: Analytes of hemoglobin metabolism - porphyrins, iron, and bilirubin. In Tietz Textbook 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 BookCompany, 2001, pp 2991-3062
Method Description Describes how the test is performed and provides a method-specific reference
An aliquot of urine is acidified and mesoporphyrin is added as an injection marker. Porphyrins in the acidified urine are separated by high-performance liquid chromatography (HPLC) and the eluted porphyrins are quantified by comparison of their fluorescence intensity to that of known porphyrin standards.(Ford RE, Ou C-N, Ellefson RD: Liquid chromatographic analysis for urinary porphyrins. Clin Chem 1981;27:397)
Porphobilinogen (PBG) in urine is quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) after addition of stable isotope-labeled PBG internal standard and solid-phase extraction.(Ford RE, Magera MJ, Kloke KM, et al: Quantitative measurement of porphobilinogen in urine by stable-isotope dilution liquid chromatography-tandem mass spectrometry. Clin Chem 2001 September;47:1627-1632)
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; 7 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.
2 days (not reported Saturday or Sunday)
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.
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.
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.
84120-Porphyrins, quantitation and fractionation
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.
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