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Test Code VALP Valproic Acid LAB24

Test Method

Particle Enhanced Turbidimetric Inhibition Immunoassay; Beckman DXC600


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.

Useful For

Monitoring therapy

Assessing compliance

Evaluating potential toxicity

Specimen Requirement

0.5 mL serum or plasma is required.

CPT Code Information

80164 Therapeutic Drug Levels: Dipropylacetic acid
(valproic acid)

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.

LOINC Code Information

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

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.