Aminolevulinic Acid Dehydratase (ALAD), Whole Blood
Test Mnemonic
ALADWB
CPT Codes
- 82657 - QTY (1)
Aliases
- ALAD Deficiency Porphyria
- Doss Porphyria
Performing Laboratory
Mayo Clinic Dpt of Lab Med & Pathology
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 5 mL | Whole blood | Sodium heparin (Green) | Place specimen on ice after draw. | Refrigerated | Fill tube completely. Patient should abstain from alcohol for 24 hours. Include a list of medications the patient is currently taking. Send specimen to Cleveland Clinic Laboratories on the day of collection. Sending in the original tube is preferred, but not required. |
Alternate Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 5 mL | Whole blood | EDTA (Lavender) | Place specimen on ice after draw. | Refrigerated | Fill tube completely. Patient should abstain from alcohol for 24 hours. Include a list of medications the patient is currently taking. Send specimen to Cleveland Clinic Laboratories on the day of collection. Sending in the original tube is preferred, but not required. |
| 5 mL | Whole blood | Lithium heparin (Green) | Place specimen on ice after draw. | Refrigerated | Fill tube completely. Patient should abstain from alcohol for 24 hours. Include a list of medications the patient is currently taking. Send specimen to Cleveland Clinic Laboratories on the day of collection. Sending in the original tube is preferred, but not required. |
Minimum Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 3 mL |
Stability
| Environmental Condition | Description |
|---|---|
| Ambient | 4 days |
| Frozen | Unacceptable |
| Refrigerated | 7 days (preferred) |
Days Performed
Tue, Thu
Turnaround Time
4 - 5 days
Methodology
| Name | Description |
|---|---|
| Enzymatic End Point | |
| Spectrofluorometric |
Reference Range
| ALA Dehydratase | |||||
|---|---|---|---|---|---|
| Sex | Age From | Age To | Type | Range | Range Unit |
| Freetext | > or = 4.0 nmol/L/sec; Reference ranges have not been established for patients < 16 years old | Freetext | 3.5 - 3.9 nmol/L/sec (indeterminate); Reference ranges have not been established for patients < 16 years old | Freetext | < 3.5 nmol/L/sec (diminished); Reference ranges have not been established for patients < 16 years old |
Special Info
Patient Prep: Patient should abstain from alcohol for 24 hours prior to collection. Include a list of medications the patient is currently taking. After collection, immediately place specimen in an ice bath. Hemolyzed specimens (mild to grossly hemolyzed) are unacceptable. Ambient or frozen whole blood will be rejected. Informed consent is required for New York clients. Note: Testing is not reported on Saturday or Sunday.
Clinical Info
Preferred test for the confirmation of a diagnosis of aminolevulinic acid dehydratase deficiency porphyria. 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 method will not exhibit a decreased ALAD enzyme activity due to lead intoxication. Porphyrias are a group of inherited disorders resulting from enzyme defects in the heme biosynthetic pathway. A defect in the second enzyme of this pathway causes 5-aminolevulinic acid (ALA) dehydratase (ALAD) deficiency porphyria (ADP). A marked deficiency of ALAD causes the accumulation and subsequent urinary excretion of large amounts of ALA. Urinary porphobilinogen (PBG) remains essentially normal, which rules out other forms of acute porphyria. ADP is a rare autosomal recessive acute hepatic porphyria that produces neurologic symptoms similar to those seen in acute intermittent porphyria. Symptoms include acute abdominal pain, peripheral neuropathy, nausea, vomiting, constipation, and diarrhea. Respiratory impairment, seizures, and psychosis are possible during an acute period. The workup of patients with a suspected porphyria is most effective when following a stepwise approach. Cautions: This assay is not useful in assessment of lead intoxication as it reactivates ALAD that has been inhibited by lead. Abstinence from alcohol is essential for at least 24 hours prior to specimen collection as ethanol suppresses ALAD activity. False-positive values may result from enzyme degradation due to improper specimen handling.