Nov 5, - Variables that influence how long Klonopin stays in your system . Urine tests: A urine test involves collection of a fresh urine sample that is. Blood, swab and urine tests can detect the drug for up to days, while hair tests that the following factors determine how long Klonopin will stay in your System: Urinalysis is the most preferred method for the detection of Klonopin and its. This is a urine test to screen for a class of medicines called benzodiazepines. Benzodiazepines are central nervous system depressants. Blood tests are also harder for a patient to alter to hide drug abuse. Alprazolam (Xanax), clonazepam (Klonopin), temazepam (Restoril), and triazolam (Halcion) may not be found in.