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oth 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 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.
Useful For: Preferred screening test during symptomatic periods for acute intermittent porphyria,
hereditary coproporphyria, and variegate porphyria (additional confirmatory testing is required to
establish a diagnosis) Preferred screening test to begin assessment for congenital erythropoietic porphyria
and porphyria cutanea tarda (additional confirmatory testing is required to establish a diagnosis)
Interpretation: 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.
Reference Values:
UROPORPHYRINS (octacarboxyl)
< or =30 nmol/24 hours
HEPTACARBOXYLPORPHYRINS
< or =9 nmol/24 hours
HEXACARBOXYLPORPHYRINS
< or =8 nmol/24 hours
PENTACARBOXYLPORPHYRINS
< or =10 nmol/24 hours
COPROPORPHYRINS (tetracarboxyl)
Males: < or =230 nmol/24 hours
Females: < or =168 nmol/24 hours
PORPHOBILINOGEN
< or =2.2 mcmol/24 hours
Clinical References: 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
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