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HelpTest Code VPA Valproic Acid, Total
Useful For
Valproic acid or valproate is a drug that is used for control of seizures. If serum or plasma levels of the drug are too low, seizure control is not maintained, and if serum or plasma levels are too high, the risk of toxicity increases.
Synonyms/Keywords
Valproate, Dipropylacetic Acid, Divalproex, Valproic Acid (Depakene), Valproic Acid (Depakote) 2-propylpentanoic acid
Specimen Requirements
| Fasting Required | Specimen Type | Preferred Container/Tube | Acceptable Container/Tube | Specimen Volume | Specimen Minimum Volume (allows for 1 repeat) |
Pediatric Minimum Volume (no repeat) |
|---|---|---|---|---|---|---|
| No | Serum/ Plasma | Serum Separator Tube (SST), Lithium-heparin Plasma Separator (PST) | Red Top Tube (RTT), Lithium-heparin Green Top Tube (GTT) | 0.5 mL | 0.2 mL |
Collection/Processing Instructions
Indicate time of collection.
Indicate if collection is from a Peak or Trough collection.
For Trough: Collect just prior to next dose.
For Peak: Collect 1-3 hours after oral dosing.
Specimen should be centrifuged and separated within 2 hours of collection.
Pharmacokinetic factors influence the correct time of peak sample collection after the last drug dose. These factors include dosage form, mode of administration, and biological variations affecting drug disposition.
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum/Plasma | Refrigerate | 2 hours |
| Freeze | 1 year |
Interpretations
Time to steady state (adult/child): 60-80 hours/40-48 hours.
Time to peak level: 0.5-1.5 hours.
Drug is highly protein bound.
Valproate has been reported to increase serum levels of amitriptyline and other tricyclic antidepressants.
Reference Range Information
| Performing Location | Reference Range |
|---|---|
| All Performing Sites |
Therapeutic: 50-100 ug/mL
Optimal response is usually observed when the trough level is >50 ug/mL. Peak levels should not exceed 100 ug/mL. |
| See Critical Value List for list of current critical values | |
Marshfield Labs Performing Department
Marshfield Labs Chemistry
Performing Information
| Performing Location | Day(s) Test Performed | Analytical Time | Methodology/Instrumentation |
|---|---|---|---|
| Marshfield | Monday through Sunday | Less than 2 hours |
Emit* 2000 Rate Assay/Beckman AU |
CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 80164 |
Outreach CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 80164 |
Ordering Applications
| Ordering Application | Description |
|---|---|
| Cerner | Valproic Acid Level |