Hello from JustAnswer. This is Dr. Love and I will be glad to assist you today.
There are two levels of answer to this question.
From the perspective of how long the Klonopin is in the system, the Klonopin can still be detectable on Monday after last use on Wednesday.
However, the standard urine screening test for benzodiazepines will frequently not detect Klonopin. The standard benzodiazepine test is oriented towards several of the common benzodiazepines that are metabolized via a common pathway, including Valium, Librium, Tranxene, and Restoril. The Klonopin is metabolized differently, so is frequently missed by the standard benzodiaepine drug screening test. It is possible to perform a screening test for Klonopin, but it would need to be a separate test, so is usually not included in standard pre-employment drug testing programs.
If the urine is sent for a confirmatory test, it would be able to detect each of the various benzodiazepines. But if the screening test is negative, the urine would typically not be sent for a confirmatory test.
So, while Monday would still be in the testing window for Klonopin, a standard pre-employment drug screening test will frequently miss the drug.
If I can provide any additional information, please let me know.