Δ-Aminolevulinic Acid, 24-Hour Urine

TEST: 096354
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CPT: 82135
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Synonyms

  • ALA, Delta, 24-Hour Urine
  • Delta Aminolevulinic Acid, 24-Hour Urine

Special Instructions

Measure and record total 24-hour urine volume on the test request form. Order Δ-Aminolevulinic Acid, Random Urine [007364] for random urine testing.

Expected Turnaround Time

3 - 6 days

Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.

Related Information

Related Documents

Specimen Requirements

Specimen

Urine (24-hour), frozen and protected from light

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

Instruct the patient to void at 8 a.m. (or 8 p.m.) and discard the specimen. Then collect all the urine, including the final specimen voided at the end of the 24-hour collection period (i.e., 8 a.m. [or 8 p.m.] the following day), in the 24-hour collection container (Labcorp No. 23301). Specimen must be kept refrigerated during collection. Measure and record on the test request form the 24-hour total volume. Mix well. pH must be <7. Transfer the urine into a Labcorp amber plastic frozen transport tube with amber cap (Labcorp No. 78656). Label the container with the patient's name, date and time collection started and finished. The specimen should be frozen immediately and maintained frozen until tested. (If amber tube and cap are not available, cover a clear plastic transport tube completely from top to bottom with aluminum foil. Identify the specimen with the patient's name directly on the transport tube and the outside of the aluminum foil. Secure with tape).

Storage Instructions

Freeze immediately and protect from light. Note: Urine is not stable preserved with sodium carbonate. It is stable for one month when preserved with 30% acetic acid and frozen (-20°C to 0°C), or stable for three days with 30% acetic acid 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

Test Details

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.

Limitations

ALA may be normal during latent period of acute intermittent porphyria, hereditary coproporphyria, porphyria variegata. For the diagnosis of lead poisoning, measurement of blood and urine lead, and free erythrocyte protoporphyrin are other available options.

This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.

Methodology

Column chromatography; Ehrlich reagent − spectrophotometry

Reference Interval

0.5−5.1 mg/24 hours

Additional Information

Conversion of ALA to porphobilinogen is inhibited by lead and mercury; thus, lead poisoning causes increased urinary Δ-ALA, as well as increases of coproporphyrin and of free erythrocyte protoporphyrin.

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
096354 ALA Delta, 24-Hour Urine 26974-6 096355 Delta ALA mg/L 26974-6
096354 ALA Delta, 24-Hour Urine 26974-6 096356 Delta ALA mg/24 hr 2200-4

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