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Test Code VALP Valproic Acid

Important Note

Order LAB24

Performing Laboratory

 YRMC Laboratory

Day(s) Test Set Up

Monday through Sunday

Specimen Requirements

LT Green/Mint Top (NAHEP)
Minimum Draw Volume: 2mL

For patients receiving valproic acid orally collect specimen 30 minutes prior to next dose.

Order of Draw

BD Vacutainer Blood Collection System

Specimen Transport Temperature

Stability- Refrigerated Up to 24 hours from the time of collection.
Stability- Ambient Up to 8 hours from the time of collection.
If specimens cannot be centrifuged, they must be received in the laboratory within 2 hours.
 

CPT Code

80164

Unit of Measure

ug/mL

Patient Preparation

  • Pharmacokinetic factors including dosage form, mode of administration and biological variation can influence the appropriate time of sample collection following administration of valproic acid.
  • Valproic acid monitoring is most appropriate when the blood sample is drawn after steady-state conditions have been reached (after 4 – 5 half-lives on an unchanged dose regimen).
  • For patients receiving valproic acid orally the blood sample should be drawn immediately before the next dose because of its short half-life.7
  • Valproic acid samples should be monitored at a consistent time of day because concentration is affected by circadian rhythm.