Reference Interval:
| Test Number
| Components
| Therapeutic Range
| | | Valproic Acid, Total
| Therapeutic Range: 50-125 µg/mL
Toxic: Greater than 150 µg/mL
| | | Valproic Acid, Free
| Therapeutic Range: 6-22 µg/mL
Toxic: Greater than 50 µg/mL
| | | VPA- % Free
| 5-18%
|
|
| Interpretive Data: |
Free valproic acid may be important to monitor in patients with altered or unpredictable protein binding capacity because valproic acid exhibits variable, dose-dependent protein binding. Valproic acid is also subject to drug-drug interactions due to displacement of protein binding. Calculating percent free attempts to minimize differences in assay cross-reactivity and may be useful in dose optimization.
|
| CPT Code(s): |
80164 VPA, total; 80164 VPA, free
|
Cross References: |
Depakene, Free, Depakote, Free, Free Valproate |