Δ-Aminolevulinic Acid, 24-Hour Urine
Also known as: ALA, Delta, 24-Hour Urine, Delta Aminolevulinic Acid, 24-Hour Urine
Use
Diagnose porphyrias: Δ-ALA may be increased in attacks of acute intermittent porphyria; evaluation of certain neurological problems with abdominal pain; diagnosis of lead or mercury poisoning. Urinary Δ-ALA is not a sensitive indicator of lead poisoning in children because it does not increase until blood lead concentration is 40 μg/dL, well above the recommended level. ALA is increased also in tyrosinemia. Porphobilinogen and δ-aminolevulinic acid are the tests of choice for acute intermittent porphyria.
Special Instructions
It is important to measure and record the total 24-hour urine volume on the test request form for accurate assessment. For cases requiring random urine testing, order the Δ-Aminolevulinic Acid, Random Urine test (Test Code: 007364).
Limitations
Δ-ALA levels may be normal during the latent periods of acute intermittent porphyria, hereditary coproporphyria, and porphyria variegata. In cases of suspected lead poisoning, blood and urine lead concentrations, as well as free erythrocyte protoporphyrin levels, are typically measured for a more comprehensive assessment.
Methodology
Other
Biomarkers
LOINC Codes
- 26974-6
- 26974-6
- 2200-4
Result Turnaround Time
3-6 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
3 mL aliquot
Minimum Volume
1 mL aliquot
Container
Plastic 24-hour urine container with 30 mL of 30% acetic acid (Labcorp No. 23301) and amber plastic frozen transport tube and cap (Labcorp No. 78656)
Collection Instructions
Instruct the patient to void at 8 a.m. (or 8 p.m.) and discard the specimen. Collect all urine including the final specimen voided at the end of the 24-hour period. Refrigerate during collection. Measure and record the total volume. Mix well, ensure pH <7, transfer to amber tube, label properly, and freeze immediately.
Storage Instructions
Freeze immediately and protect from light. Stable for one month when preserved with 30% acetic acid and frozen (-20°C to 0°C), or stable for three days when refrigerated (2°C to 8°C).
Causes for Rejection
Specimen not protected from light; use of preservative other than 30% acetic acid; use of sodium carbonate preservative
Stability Requirements
| Temperature | Period |
|---|---|
| Refrigerated | 3 days |
| Frozen | 1 month |