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HelpTest Code ALAUR Aminolevulinic Acid, Urine
Reporting Name
Aminolevulinic Acid, UUseful For
Assisting in the differential diagnosis of the acute hepatic porphyrias
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
UrineOrdering 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 |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Special Instructions
Reference Values
<1 year: ≤10 nmol/mL
1-17 years: ≤20 nmol/mL
≥18 years: ≤15 nmol/mL
Day(s) Performed
Tuesday, Thursday
CPT Code Information
82135
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| ALAUR | Aminolevulinic Acid, U | 34284-0 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 61547 | Aminolevulinic Acid, U | 34284-0 |
| 34347 | Interpretation (ALA), U | 59462-2 |
| 34348 | Reviewed By | 18771-6 |
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
Interpretation
Abnormal results are reported with a detailed interpretation that may include an overview of the results and their significance, a correlation to available clinical information provided with the specimen, differential diagnosis, 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
No significant cautionary statements
Method Description
Aminolevulinic acid (ALA) is determined by liquid chromatography tandem mass spectrometry (LC-MS/MS) stable isotope dilution analysis. The urine is mixed with an internal standard ([13]C5, [15]N ALA-IS) and filtered using a 0.2 mcM nylon filter vial. The ratios of the extracted peak areas of ALA to ALA-IS determined by LC-MS/MS are used to calculate the concentration of ALA present in the sample.(Lacey, JM, Magera MJ, Tortorelli S: Delta aminolevulinic acid quantitation in urine by LC-MS/MS. J Am Soc Mass Spectrom. 2011;22, S1:pp 69)
Report Available
3 to 7 daysTest 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.Disease States
- Porphyria