AMINOLEVULINIC ACID, URINE, 24-HOUR

Code
000.0000
Name
AMINOLEVULINIC ACID, URINE, 24-HOUR
Category
None
Department
Send-Out
Start Date
Expiration Date
Synonyms
ALA
CPT Codes
82135
Site
SBMF
Reference Test
44169
ATLAS Test Code

Specimen Information

Type

Urine, 24-Hour

Volume

4.0 ml

Transport Info

Transfer urine to a light-protected (amber-colored) plastic container with tightly fitting lid (no preservative) OR wrap container in foil
Refrigerated

Fasting Required?
False
Patient Instructions

Refrain from alcohol consumption 24 hours prior to collection.

Reference Range

See Report

Methodology

Ion Exchange Chromatography/Spectrometry

Clinical Significance

Slight elevations of ALA may be seen in association with exposure to alcohol, lead, and a variety of other agents. Significant elevations are often associated with the acute porphyrias (massive elevations of porphobilinogen [PBG]). Significant elevations are also seen in hereditary tyrosinemia.

The most common reason for an elevated urine aminolevulinic acid (ALA) level is exposure to an agent that has inhibited the activity of the enzyme porphobilinogen (PBG) synthase in the biosynthetic pathway of porphyrins and heme. Common mechanisms include acute and chronic exposure to alcohol, lead, and other heavy metals. Significant elevations are seen also in hereditary tyrosinemia. Abnormal concentrations of ALA can accumulate in the acute neurologic forms of the porphyrias. The signs and symptoms of the porphyrin disorders are diverse and include acute abdominal pain, peripheral neuropathies (burning, itching, loss of feeling in the extremities), and behavioral changes that may induce depression or acute psychosis. The preferred approach to the laboratory diagnosis of an acute porphyria is the determination of porphobilinogen (PBG) in urine. Specimen preservation with acid or base may cause assay interference and is discouraged. When collecting urine for additional tests that require acid or base preservation, the ALA aliquot should be removed prior to the addition of the acid or base.

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