Hydrocodone can be detected in the urine for 3-4 days. A blood test can identify Hydrocodone for up to 24 hours. A saliva test can detect Hydrocodone for up to 1-4 days. Hydrocodone, like many other drugs, can be detected with a hair follicle drug test for up to 90 days. Hydrocodone is prescribed for people with severe pain who need the medication 24 hours a day.