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Test Code VALP Valproic Acid LAB24

Test Method

Particle Enhanced Turbidimetric Inhibition Immunoassay; Beckman DXC600

Specimen Requirement

0.5 mL serum or plasma is required.

Reference Values

50.0-100.0 mcg/mL

  • Toxic Level:  >125 mcg/mL

In practice, therapeutic efficacy with this drug often requires
steady-state concentrations somewhat higher than the conventional
upper limit shown above.


Testing is performed Monday through Sunday.

Routine: Typically completed within 4 hours after the
specimen arrives at the testing site.

STAT: Typically completed within 1 hour after the specimen
arrives at the testing site.

CPT Code Information

80164 Therapeutic Drug Levels: Dipropylacetic acid
(valproic acid)

LOINC Code Information

4086-5 Valproate [Mass/Volume] In Serum Or Plasma

Useful For

Monitoring therapy

Assessing compliance

Evaluating potential toxicity

Additional Specimen Collection Information

Collect blood in a lithium heparin, green-top or
red-top tube. Serum and plasma gel tubes are not acceptable.

Peak specimens should be
collected as follows:

  • 0.5-1 Hour for syrup
  • 2-8 Hours for capsule
  • 3-7 Hours for enteric coated tablet

Trough level is collected just prior
to next dose.

Serum or plasma should be separated from contact with the cells
within 2 hours of collection. Specimens not centrifuged within 4
hours of collection may be rejected. Refrigerate the specimen
if unable to assay within 8 hours of collection. Samples with
>2+ lipemia must be cleared prior to analysis.