Librium is detected on testing anywhere from six hours to six weeks after the last dose. The length of time that Librium is detectable in the body depends on several factors, including the test used and the metabolism rate, age, hydration level and health status of the individual, says About.com.
Blood tests for the presence of Librium detect it after six hours and up to 48 hours after ingestion, according to About.com. A saliva test detects the presence of Librium for up to 10 days, and a urine test detects it for up to six weeks. Tests of hair strands detect Librium for up to 90 days after ingestion. These are approximations, and Librium may be detected in the body for longer than these periods.