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HelpTest Code ALAD Aminolevulinic Acid Dehydratase, Whole Blood
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Reporting Name
ALA Dehydratase, WBSpecimen Type
Whole bloodOrdering 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.
Reject Due To
| Gross hemolysis | Reject |
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole blood | Refrigerated (preferred) | 7 days |
| Ambient | 4 days |
Specimen Minimum Volume
3 mL
Special Instructions
Day(s) Performed
Tuesday
Specimen Retention Time
14 daysReport Available
2 to 8 daysReference 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.
Useful For
Preferred confirmation test for the diagnosis of aminolevulinic acid dehydratase deficiency porphyria
This test is not useful for detecting lead intoxication.
Testing Algorithm
The following algorithms are available:
-Porphyria (Acute) Testing Algorithm
CPT Code Information
82657
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| ALAD | ALA Dehydratase, WB | 12916-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 4021 | ALA Dehydratase | 12916-3 |
| 28399 | Interpretation | 59462-2 |
| 606468 | Reviewed By | 18771-6 |
Method Description
Measurement of aminolevulinic acid (ALA) dehydratase activity is based on the rate of synthesis of uroporphyrin from ALA in incubated, lysed erythrocytes. Low yield of uroporphyrin from ALA indicates a deficiency of ALAD.(Unpublished Mayo method)
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.
Forms
New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available: