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The University of Chicago Medicine Laboratories

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Specimen Collection and Handling

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Mayo Clinic Laboratories

Test Code VALP Valproic acid

Specimen and Container/Tube

Specimen Type: Serum

Preferred Specimen: Red Top

Other Acceptable specimens: None

Volume

Preferred Volume: 0.5 mL

Minimum Volume: 0.2 mL

Specimen Stability

Storage Temperature

Stability

Room temperature

2 days

Refrigerated

7 days

Frozen

3 months

Collection Instructions

Collect specimen per standard laboratory collection procedures. 

 

Collect at designated intervals for peak or trough testing. 

  • Peak level:       30 min after completion of dose
  • Trough level:   30 min before next dose

Specimen Handling and Transport Instructions

UCMC Onsite Instructions: 

Collect specimen per standard collection procedure and send to laboratory immediately. 

 

UCMC Offsite and UC MedLab Outreach Instructions: 

  • Samples should be centrifuged within 2 hours of collection.
  • Centrifuge specimens at >2500 x g for 10 minutes at room temperature.
  • Aliquot sample into plastic transport tube containing a minimum of 0.2 mL of specimen.
  • Samples must be sent refrigerated at 2-8oC.

Rejection Criteria

  • Common specimen rejected situations include: incorrect specimen type, insufficient volume, missing or incomplete specimen identifiers, incorrect specimen transport, or specimens outside stability limits. 
  • Specimens that are clotted or grossly hemolyzed.
  • Specimens that were transported unspun/whole blood and draw time is greater than 6 hours.

Reference Values

Test

Age

Sex

Reference Range

Valproic Acid

All

All

50 - 100 μg/mL

Critical Values

Analyte

Unit

Low

High

Age

Valproic Acid

μg/mL

N/A

>200

All

Turnaround Time

Turnaround times are relative to the time the specimen is received in the test laboratory. 

 

STAT Turnaround Time: 1 hour

Routine Turnaround Time: 4 hours

Testing Schedule: 24/7

Clinical Indications

Useful for monitoring therapy, assessing compliance and evaluating potential valproic acid toxicity.

Test Components

Valproic acid
 

Methodology

Homogeneous Enzyme Immunoassay Technique (EMIT) (Roche Diagnostics)

CPT Codes

80164

LOINC Codes

4086-5

Synonyms/Keyword Search

Depakote, VPA, VALP2, VALPROIC.

Additional Information

  • Results should always be assessed in conjunction with patient's medical history, clinical examination and other findings.
  • Co-administration of other anti-epileptic drugs can significantly affect valproic acid metabolism. Several factors complicate interpretation of valproic acid levels, including time interval between drug administration and blood sampling, the type of seizures treated, albumin concentration and factors affecting albumin binding of valproic acid , and the presence of other anti-epileptic drugs and pharmacologically-active metabolites of valproic acid.
  • Collection time varies dependent upon desired measurement of peak or trough values.

Last Review Date

8/19/2024