Comparison of enzyme immunoassay and gas chromatography for determination of carbamazepine and ethosuximide in human serum.

Patients' sera were analyzed for carbamazepine and ethosuximide by enzyme immunoassay (x) and gas chromatography (y), and the results were compared. The correlation coefficients were: for carbamazepine, x vs. y 0.94 (n = 93); for ethosuximide, x vs. y 0.99 (n = 30). These results suggest that the two methods could be used interchangeably. Ten serum samples supplemented with carbamazepine (2.5 to 12.5 mg/liter) and ethosuximide (20.0 to 130.0 mg/liter) were analyzed by both methods. The correlation coefficients were: x vs. y 0.99 (n = 10) for carbamazepine and x vs. y 0.99 (n =10) for ethosuximide.