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Test Code ALAUR Aminolevulinic Acid, Urine

Reporting Name

Aminolevulinic Acid, U

Useful For

Assisting in the differential diagnosis of the acute hepatic porphyrias

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Urine


Ordering Guidance


The preferred test for lead toxicity in children is blood lead; order either PBDV / Lead, Venous, with Demographics, Blood or PBDC / Lead, Capillary, with Demographics, Blood.



Necessary Information


Patient's age is required.



Specimen Required


Patient Preparation: Patient should not consume any alcohol for 24 hours before specimen collection.

Supplies: Urine Tubes, 10 mL (T068)

Collection Container/Tube: Clean, plastic urine collection container

Submission Container/Tube: Plastic vial

Specimen Volume: 2 mL

Collection Instructions: Collect a random urine specimen.


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Refrigerated (preferred) 28 days
  Frozen  45 days

Reference Values

<1 year: ≤10 nmol/mL

1-17 years: ≤20 nmol/mL

≥18 years: ≤15 nmol/mL

Day(s) Performed

Tuesday, Thursday

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

82135

Disease States

  • Porphyria

Clinical Information

The porphyrias are a group of inherited disorders resulting from enzyme defects in the heme biosynthetic pathway. Depending on the specific enzyme involved, various porphyrins and their precursors accumulate in different specimen types. The patterns of porphyrin accumulation in erythrocytes and plasma and excretion of the heme precursors in urine and feces allow for the detection and differentiation of the porphyrias. For more information see The Heme Biosynthetic Pathway.

 

The porphyrias are typically classified as erythropoietic or hepatic based upon the primary site of the enzyme defect. In addition, hepatic porphyrias can be further classified as chronic or acute, based on their clinical presentation.

 

The primary acute hepatic porphyrias: aminolevulinic acid dehydratase deficiency porphyria (ADP), acute intermittent porphyria (AIP), hereditary coproporphyria (HCP), and variegate porphyria (VP), are associated with neurovisceral symptoms that typically onset during puberty or later. Common symptoms include severe abdominal pain, peripheral neuropathy, and psychiatric symptoms. A broad range of medications (including barbiturates and sulfa drugs), alcohol, infection, starvation, heavy metals, and hormonal changes may precipitate crises. Photosensitivity is not associated with AIP, but it may be present in HCP and VP.

 

The excretion of aminolevulinic acid (ALA) can be increased due to one of the inherited acute porphyrias or due to secondary inhibition of ALA dehydratase. Among the secondary causes, acute lead intoxication results in the greatest increases of aminolevulinic aciduria. Less significant elevations are seen in chronic lead intoxication, tyrosinemia type I, alcoholism, and pregnancy. Once the biochemical diagnosis of an acute porphyria is established, molecular genetic testing is available (APGP / Acute Porphyria Gene Panel, Varies), which allows for diagnosis of at-risk family members.

 

For more information, see the following or call 800-533-1710 to discuss testing strategies:

-The Heme Biosynthetic Pathway

-Porphyria (Acute) Testing Algorithm

-Porphyria (Cutaneous) Testing Algorithm

Report Available

3 to 7 days

Reject Due To

  All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Method Name

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)