How Long Does Cocaine Stay in Your Body?
Like many other drugs, cocaine can be detected in the urine, blood and hair from few hours to several months after its use. Period during which cocaine stays in the body depends on a cocaine dose, form, frequency and duration of use, body mass, age and individual metabolic (breakdown) rate.
Urine Test for Cocaine
Cocaine can be detected in the urine for 4-8 hours after a single snorted (nasal) dose, and up to 24 hours after a single ingested (oral) dose (1).
A breakdown product of cocaine, benzoylecgonine can be detected in the urine for up to 60 hours after a single use, or up to 22 days after repeated use (1). Other metabolites detected in urine after cocaine use: ecgonine methyl ester, cocaethylene (when cocaine is taken by alcohol) (3).
The ratio of benzoylecgonine to cocaine in the urine less than 100:1 speaks for cocaine use (or leakage from a body package) less than 10 hours before collection of the urine sample (1). The exact time and the dose of cocaine used cannot be determined by urine tests, though.
Blood Test for Cocaine
Cocaine in the blood is detectable from few minutes and up to 5-6 hours after a single dose (2). Blood tests for cocaine are expensive.
Hair Test for Cocaine
Cocaine may appear in the hair as soon as 8 hours or sometimes only 7-10 days after a single use and can stay there for months – until the hair is cut. The amount of cocaine and time when it was used cannot be reliably determined by a hair test (4).
Hair can be contaminated with cocaine from the outside. Washing the hair may remove most of such cocaine, but not necessary all of it. Eventual contamination with this ‘second hand’ cocaine is usually checked in the laboratory before proceeding with the hair test.
Saliva Cocaine Testing
Cocaine can be detected in saliva shortly after nasal (snorting), oral (smoking, ingesting) or intravenous (injecting) use and up to one day thereafter (but often only for 6 hours or less) (5).
Sweat Patch Test for Cocaine
Sweat patch tests for cocaine are usually performed by non-medical personnel and are often false positive (6).
Are False POSITIVE Results of Cocaine Tests Possible?
An antibiotic amoxicillin (7) and local anesthetic Novocaine or lidocaine (used in dentistry) were often mentioned as possible causes of false positive results for cocaine, but this has been not proven.
Drinking coca tea (8), chewing coca leaves, passive inhaling of cocaine (crack) smoke and using cocaine eye drops may result in a positive urine test for cocaine.
Kidney, liver infection, diabetes, tonic water.
Are False NEGATIVE Results of Cocaine Tests Possible?
Using certain detox kits and drinking water before testing can result in a negative urine test for cocaine in some laboratories, but substances (adulterants) used can be detected if specifically checked (9).
General Notes About Cocaine Testing
- Home cocaine detection kits are not reliable.
- Bleaching or coloring the hair, using any shampoo or other substance cannot remove cocaine from the hair.
- Cocaine ‘detox kits’ do not remove cocaine from the hair.
- Substances added to the urine to cheat can be detected by the laboratory.
- Cocaine in the urine (emedicine.medscape.com)
- Cocaine in the blood and urine (drugdetection.net)
- Cocaine metabolites detected in testing samples (ag.ca.gov)
- Cocaine in the hair (druglibrary.org)
- Saliva cocaine testing (toxlab.co.uk)
- Sweat patch test for cocaine may be false positive (drugpolicy.org)
- Amoxicillin not likely causes false positive cocaine tests (pubmed.org)
- Drinking coca tea results in a positive urine cocaine test (journals.lww.com)
- Adulterants added to a urine sample can be detected by the lab (clinchem.org)
Article reviewed by Dr. Greg. Last updated on July 30, 2012