Valproic Acid, Total and Free

Test Code

VALPTF

Quest Code

6651

CPT Codes
80164, 80165

Preferred Specimen

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

Patient Preparation
Collect as a 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, 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: 30 days

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

Serum separator tube (SST)

Methodology

Immunoassay (IA)

Setup Schedule

Set up: Mon-Sat; Report available: Next day

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
14225 Newbrook Dr
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.