Δ-Aminolevulinic Acid, 24-Hour Urine

Also known as: ALA, Delta, 24-Hour Urine, Delta Aminolevulinic Acid, 24-Hour Urine

Clinical Use

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

Not provided.

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.

Test Details

Methodology

Other

Biomarkers

Δ-Aminolevulinic Acid

Analyte

Δ-ALA Level

Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

LOINC Codes

Order Codes

26974-6 - D-ALA 24h Ur-mCnc

Result Codes

26974-6 - D-ALA 24h Ur-mCnc
2200-4 - D-ALA 24h Ur-mRate

Result Turnaround Time

3-6 days

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).