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Test Code ALAD Aminolevulinic Acid Dehydratase, Whole Blood

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Whole blood


Ordering Guidance


This test is not useful in assessment of lead intoxication as it reactivates aminolevulinic acid dehydratase that has been inhibited by lead. The preferred test for lead toxicity is PBDV / Lead, Venous, with Demographics, Blood.



Necessary Information


1. Patient’s age is required

2. Include a list of medications the patient is currently taking.



Specimen Required


Patient Preparation: For 24 hours before specimen collection, patient must not consume any alcohol. This is essential as ethanol suppresses aminolevulinic acid dehydratase activity, leading to false-positive results.

Container/Tube:

Preferred: Green top (sodium heparin)

Acceptable: Lavender top (EDTA) or green top (lithium heparin)

Specimen Volume: 4 mL; full tube

Collection Instructions: Refrigerate specimen as soon as possible.


Specimen Minimum Volume

3 mL

Specimen Stability Information

Specimen Type Temperature Time
Whole blood Refrigerated (preferred) 7 days
  Ambient  4 days

Reference Values

≥4.0 nmol/L/sec

3.5-3.9 nmol/L/sec (indeterminate)

<3.5 nmol/L/sec (diminished)

 

Reference ranges have not been established for patients who are younger than 16 years.

Day(s) Performed

Tuesday

CPT Code Information

82657

Genetics Test Information

Aminolevulinic acid dehydratase (ALAD) activity can be inhibited in situations including hereditary tyrosinemia type 1, lead intoxication, and exposure to styrene, trichloroethylene, or bromobenzene. These causes should be ruled out when considering a diagnosis of ALAD deficiency porphyria (ADP). This test will not detect decreased ALAD enzyme activity due to lead intoxication.

Report Available

2 to 8 days

Specimen Retention Time

14 days

Reject Due To

Gross hemolysis Reject