Ordering Recommendation

Optimize drug therapy and monitor patient adherence.

Mnemonic
ETHOSUX
Methodology

Quantitative Enzyme Immunoassay

Performed

Sun-Sat

Reported

1-5 days

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation

Timing of specimen collection: Pre-dose (trough) draw - At steady state concentration.

Collect

Plain Red. Also acceptable: Lavender (K2or K3EDTA) or Pink (K2EDTA).

Specimen Preparation

Separate serum or plasma from cells ASAP or within 2 hours of collection. Transfer 1 mL serum or plasma to an ARUP Standard Transport Tube. (Min: 0.5 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions

Whole blood. Gel separator tubes, light blue (citrate), or yellow (SPS or ACD solution).

Remarks
Stability

After separation from cells: Ambient: 5 days; Refrigerated: 1 week; Frozen: 2 months

Reference Interval
Test Number
Components
Reference Interval
  Ethosuximide Therapeutic: 40-100 µg/mL
Toxic: > 150 µg/mL

Interpretive Data

The therapeutic range is based on serum pre-dose (trough) draw at steady-state concentration. Toxic concentrations may cause dizziness, drowsiness and anorexia. The incidence of adverse reactions is low; however, life-threatening agranulocytosis and fatal pancytopenia have been reported. 

Compliance Category

FDA

Note
Hotline History
N/A
CPT Codes

80168

Components
Component Test Code* Component Chart Name LOINC
0090415 Ethosuximide 3616-0
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • Zarontin
Ethosuximide, Serum or Plasma