The use of gel-barrier tubes is not recommended due to slow absorption of the drug by the gel.
Depending on the specimen volume and storage time, the decrease in drug level due to absorption may be clinically significant.
Unless otherwise directed, specimen should be collected just prior to next dose
Spin and separate
Refrigerated (preferred) - 14 days
Ambient - 1 day
Frozen - 14 days
Liquid chromatography/tandem mass spectrometry (LC/MS-MS)
Therapeutic: 0.5 - 2.0 µg/mL (reported as Nordiazepam)
Potentially toxic: >5.0 µg/mL (reported as Nordiazepam)