Valproic Acid

Cleveland HeartLab Test, V

NEW YORK DOH APPROVED: YES
CPT Code: 80164
Order Code: C1350
ABN Requirement: No
Synonyms: VPA; Depakene; Dipropylacetic Acid; Depakote
Specimen: EDTA Plasma or Red Top Serum
Volume:  1.0 mL
Minimum Volume:  0.2 mL
Container: EDTA (Lavender Top) tube or Red Top (no gel barrier) tube

Collection:

EDTA Plasma:

  1. Draw and gently invert 8 to 10 times.
  2. Centrifuge for 10 minutes.
  3. Pre-squeeze transfer pipet bulb and draw off approximately 2/3 of the upper plasma layer.
    Note: This ensures that the buffy coat and red cells remain undisturbed.
  4. Aliquot plasma into labeled transport tube and cap tightly. Discard original tube.
  5. Store transport tube refrigerated at 2-8°C until ready to ship.

Red Top Serum:

  1. Collect and label sample according to standard protocols.
  2. Gently invert tube 10 times immediately after draw. DO NOT SHAKE.
  3. Allow blood to clot 30 minutes.
  4. Centrifuge for 10 minutes.
  5. Aliquot serum into a labeled transport tube and cap tightly.

Special Instructions: Sample should be collected as a trough immediately prior to the administration of the next dose of valproic acid. Write the date and time of the last dose of valproic acid on the requisition.

Transport: Store serum at 2°C to 8°C after collection and ship the same day per packaging instructions provided with the Cleveland HeartLab shipping box.

Stability:

Ambient (15-25°C): 5 days
Refrigerated (2-8°C): 7 days
Frozen (-20°C): 30 days

Causes for Rejection: Specimens other than serum; improper labeling; samples not stored properly; samples older than stability limits

Methodology: Immunoassay (IA)

Turn Around Time: 2 to 3 days

Reference Range:

Age mg/L
All Ages 50.0 – 100.0

Intended Use: The test is used to monitor therapeutic levels of valproic acid.

Clinical Significance: Valproic acid is used as an anticonvulsant to treat certain types of seizures, to prevent migraine headaches, and to prevent 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.

Additional Information: Prescription and over-the-counter medications may raise, lower, or interfere with the levels of valproic acid.

The CPT codes provided 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 payer being billed.