Valproic Acid, Free

Test Code

CPT Codes

Preferred Specimen
3 mL serum collected red-top tube (no gel)

Patient Preparation
Avoid contact of samples with plasticizers, varnishes, paint fumes, and fatty acids. Collect as a trough just before next dose (Optimum time to collect sample: 1 hour before next dose.).

Minimum Volume
1 mL

Other Acceptable Specimens
Serum collected in no additive (royal blue-top) tube • Plasma collected in an EDTA (lavender-top) or EDTA (royal blue-top) tube

Do not use gel barrier tubes. Centrifuge and immediately separate serum or plasma specimens from the cells into clean, plastic, screw-cap vial(s).
Do not use serum separator tubes. Submission of a serum separator tube will result in cancellation.

Transport Container
Plastic screw-cap vial(s)

Transport Temperature
Refrigerated (cold packs)

Specimen Stability
Room temperature: 48 hours
Refrigerated: 7 days
Frozen: 60 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Serum separator tube (SST®)

Immunoassay (IA)

Setup Schedule
Set up: Mon-Sat a.m.; Report available: Next day

Reference Range
4.8-17.3 mg/L

Clinical Significance
Valproic acid is used as an anticonvulsant to treat certain types of seizures, to prevent migraine headahces, and to treat various psychiatric illnesses such as bipolar disorder and aggression. Drugs that compete from protein-binding sites with valproic acid, can increase the concentration of valproic acid. Measurement of the free concentration is useful if toxicity is suspected.

Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.