Ethosuximide, Serum or Plasma
Also known as: ETHOSUX
Use
Optimize drug therapy and monitor patient adherence. The therapeutic range is based on serum pre-dose (trough) draw at steady-state concentration. Toxic concentrations of ethosuximide may cause dizziness, drowsiness, and anorexia. While the incidence of adverse reactions is low, life-threatening agranulocytosis and fatal pancytopenia have been reported.
Special Instructions
Timing of specimen collection is crucial. It should be a pre-dose (trough) draw at steady state concentration to ensure accurate therapeutic monitoring.
Limitations
The test measures ethosuximide concentrations to monitor therapy and adherence but does not address the direct cause of adverse reactions, which are rare but can be life-threatening. Toxicity levels must be closely monitored, especially since the range between therapeutic and toxic is relatively narrow.
New York Approved
Methodology
Immunoassay (Enzyme Immunoassay)
Biomarkers
LOINC Codes
- 3616-0
Result Turnaround Time
1-5 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.5 mL
Container
ARUP Standard Transport Tube
Collection Instructions
Pre-dose (trough) draw at steady state concentration. Collect using Plain Red, Lavender (K2or K3EDTA), or Pink (K2EDTA) tubes.
Patient Preparation
Pre-dose (trough) draw at steady state concentration.
Storage Instructions
Refrigerated.
Causes for Rejection
Whole blood, gel separator tubes, light blue (citrate), or yellow (SPS or ACD solution).
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 5 days |
| Refrigerated | 1 week |
| Frozen | 2 months |