Valproic Acid

Test Code

916

CPT Codes
80164

Preferred Specimen

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

Patient Preparation
Collect as a trough just prior to next dose.

Minimum Volume

0.2 mL

Other Acceptable Specimens

Plasma collected in an: EDTA (lavender-top), or sodium or lithium (green-top), or sodium fluoride or potassium oxalate (gray-top), or 3.2% sodium citrate (light blue-top) tubes

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

Room temperature

Specimen Stability

Room temperature: 5 days
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-Thurs p.m., Fri and Sat evenings; Report available: Next day

Reference Range

50.0-100.0 mg/L

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 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.