how long does fentanyl patch stay in the blood?
How Long Does Fentanyl Stay in Blood? Blood tests are another common drug test used to analyze drug usage. On average, fentanyl can be detected in the blood for up to 12 hours after the drug was used. Urine testing is able to detect fentanyl usage more effectively than a blood test beyond 12 hours. If you suspect someone is abusing fentanyl it may be best to use an alternative drug testing method, such as urine testing or hair follicle testing. How Long Does Fentanyl Stay in Saliva? Saliva testing is a less common drug test used to analyze drug usage. Fortunately it is able to detect fentanyl use more effectively than urine or blood testing. On average, fentanyl can be detected in saliva testing for up to 1-3 days after use. How Long Does Fentanyl Stay in Hair?