Valproic Acid, Total and Free

Test Code

6651

CPT Codes
80164, 80165

Preferred Specimen

3 mL serum collected in a red-top tube (no gel)

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

Minimum Volume

1.5 mL

Other Acceptable Specimens

Plasma collected in: EDTA (lavender-top) tube

Instructions

Do not use gel barrier tubes. Centrifuge and immediately separate serum or plasma specimens from the cells into clean transport tube.

Transport Container

Transport tube

Transport Temperature

Refrigerated (cold packs)

Specimen Stability

Room temperature: 48 hours
Refrigerated: 7 days
Frozen: 30 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Serum separator tube (SST)

Methodology

Immunoassay (IA)

Reference Range

See Laboratory Report

Clinical Significance

Valproic acid is used as an anticonvulsant to treat certain types of seizures, to prevent migraine headaches, and to treat various psychiatric illnesses such as bipolar disorder and aggression. Drugs that compete for protein-binding sites with Valproic Acid, can increase the concentration of Valproic Acid. Therapeutic drug monitoring is useful to optimize dose. Measurement of the free concentration is useful if toxicity is suspected.

Performing Laboratory

Quest Diagnostics Nichols Institute-Chantilly VA

14225 Newbrook Drive

Chantilly, VA 20151-2228

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.