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Test Code TOPS Topiramate

Specimen and Container/Tube

Specimen Type: Serum

Preferred Specimen: Red Top

Other Acceptable specimens: Plasma/Li or Sodium-Heparin Dark Green Top (No Gel Separator), Plasma/Lavendar K2 Top

Specimen Stability

Storage Temperature

Stability

Room temperature

Not acceptable 

Refrigerated

7 days

Frozen

4 weeks

Collection Instructions

Collect specimen per standard laboratory collection procedures. Recommended that serum be collected immediately prior to next dose.

 

Specimen Handling and Transport Instructions

UCMC Onsite Instructions: 

  • Collect specimen per standard collection procedure and send to laboratory immediately. Recommended that serum be collected immediately prior to next dose.

 

UCMC Offsite and UC MedLab Outreach Instructions: 

  • Recommended that serum be collected immediately prior to next dose.
  • 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

Topiramate

All

All

2-25 μg/mL

Critical Values

Not applicable 

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

  • Monitoring serum concentrations of topiramate, particularly in patients with renal disease or those coadministered phenytoin or carbamazepine.
  • Results obtained are used in the diagnosis and treatment of topiramate overdosea and in monitoring levels of topiramate to help ensure appropriate therapy.

Test Components

Topiramate

CPT Codes

80201

LOINC Codes

17713-9

Methodology

Enzyme Multiplied Immunoassay Technique (EMIT) (Roche Diagnostics)

Synonyms/Keyword Search

Topamax

Additional Information

  • Results should always be assessed in conjunction with patient's medical history, clinical examination and other findings.
  • Coadministration of phenytoin or carbamazepine decreases topiramate serum concentrations.

Last Review Date

8/19/2024

Volume

Preferred Volume: 0.5 mL

Minimum Volume: 0.2 mL