Home
HelpTest Code VALPG Valproic Acid, Free and Total, Serum
Reporting Name
Valproic Acid, Free and Total, SPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Useful For
Monitoring both total and free valproic acid levels in therapy
Assessing compliance
Evaluating potential toxicity
Method Name
VALPA: Immunoassay
VALPF: Ultrafiltration Followed by Immunoassay
Specimen Required
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 2 mL
Collection Instructions:
1. Serum gel tubes should be centrifuged within 2 hours of collection.
2. Red-top tubes should be centrifuged, and the serum aliquoted into a plastic vial within 2 hours of collection.
Specimen Type
SerumSpecimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 14 days | |
| Frozen | 28 days | ||
| Ambient | 72 hours |
Reject Due To
| Gross hemolysis | Reject |
Reference Values
VALPROIC ACID, TOTAL
Therapeutic: 50 (trough)-125 (peak) mcg/mL
Critical value: ≥151 mcg/mL
VALPROIC ACID, FREE
Therapeutic: 5-25 mcg/mL
Critical value: >30 mcg/mL
Interpretation
The generally acceptable range for total valproic acid used as a reference to guide therapy is 50 to 125 mcg/mL. The corresponding range of free valproic acid concentration for clinical reference is 5 to 25 mcg/mL.
Low free valproic acid concentration relative to these ranges may suggest inadequate dosing, whereas a high free valproic acid concentration may be associated with toxic effects.
Because the concentration of valproic acid fluctuates considerably depending on the time from last dose, interpretation of the clinical significance of the valproic acid concentration must take into consideration the timing of the blood specimen. For this reason, 2 collections are sometimes made to assess the trough and peak concentrations.
Day(s) Performed
Monday through Sunday
Report Available
Same day/1 dayTest Classification
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
VALPA-80164
VALPF-80165
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| VALPG | Valproic Acid, Free and Total, S | 57775-9 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| VALPF | Valproic Acid, Free, S | 4087-3 |
| VALPA | Valproic Acid, Tot, S | 4086-5 |
Forms
If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| VALPF | Valproic Acid, Free, S | Yes | Yes |
| VALPA | Valproic Acid, Tot, S | Yes | Yes |