Therapeutic drug management
Gel-barrier tubes are not recommended.
Dk green heparin (Li or Na), no gel
Immediately following collection, mix sample by inverting 8 - 10 times to prevent clotting
Ambient - <3 days
Frozen - OK
Liquid chromatography/tandem mass spectrometry (LC/MS-MS)
Encainide: 15 - 100 ng/mL
ODE: 100 - 300 ng/mL
MODE: 60 - 300 ng/mL
Trough levels are most reproducible.
10% of patients do not form therapeutic concentrations of the active metabolites, ODE and MODE. In these patients the recommended range for the encainide concentration is 300 - 1200 ng/mL