Does this test have other names?
Cocaine drug test, toxicology screen, tox screen, substance abuse test, drug-of-abuse test
What is this test?
A cocaine screen is a test done to find out whether you have used cocaine recently. The test can be done on your urine, saliva, blood, hair, or sweat. It looks for the presence of cocaine or one of its metabolites, or chemicals your body makes to process cocaine. The two most important metabolites of cocaine are benzoylecgonine (ben-zoyl-ECK-oh-neen) and ecgonine methyl ester (ECK-oh-neen METH-ill ES-ter).
Rapid screening tests can be done in an office or clinic. The results arrive in minutes. Because lab tests are more sensitive and reliable, positive results should always be sent to a lab for confirmation.
Why do I need this test?
You may need this test if you:
Have (or apply for) a job that requires drug testing
Apply for insurance that requires a drug test
Have been arrested and drug testing is part of your parole
Are pulled over and are suspected of driving under the influence of drugs
These are reasons your health care provider might order the test:
He or she suspects you are abusing cocaine.
You are in the emergency room with symptoms that suggest drug abuse.
You are a patient at a drug treatment clinic.
What other tests might I have along with this test?
A cocaine screen is usually done as part of a wider screening for commonly used illegal drugs. The wider drug screen usually tests for amphetamines; opioids like morphine, methadone, and heroin; and marijuana.
What do my test results mean?
Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your health care provider.
The cocaine screen results are usually reported as positive, which means cocaine or its metabolites were found, or negative, meaning no evidence of cocaine was found in your body. These results are based on a cutoff number that shows the concentration of the substance found in your urine, saliva, blood, hair, or sweat. The exact cutoff number depends on which test is used.
How is this test done?
You will probably either urinate in a cup or have saliva taken out of your mouth.
Urine is the most common sample used. A urine test can detect cocaine metabolites for two to three days after cocaine use. In heavy users, the test may be positive for up to two weeks after use.
One drawback is that people have found ways to cheat to get a false negative, meaning a negative result when the result should be positive because of cocaine use. Products promising to alter urine test results are advertised on the Internet, and cheating usually involves adding a substance to the urine to throw off the test results. To keep people from cheating, some testers will insist on watching people while they urinate in the cup, which is embarrassing.
If you provide a urine sample, the tester may test the sample right away. The result will be available in minutes. If the result is positive, the tester should send a sample to a lab for confirmation, because the rapid tests are not as accurate as a lab test.
Saliva testing is getting more popular because it's easier and less intrusive than collecting a urine sample. Saliva is usually taken from your mouth with a special device or deposited by you directly into a tube. It is harder to cheat on a saliva test because the tester commonly watches you during the whole process. The saliva test can detect cocaine or its metabolites for only about one to two days after use.
A lab can also test a sample of your blood. Your blood holds cocaine for 12 hours and benzoylecgonine for 48 hours. But a blood test is invasive and takes more time. Blood tests are usually done only if you are in the hospital and your health care provider suspects drug abuse.
Your hair can also be tested for cocaine. Hair testing can detect cocaine for months after use. It is a complicated process, though, and may not always be accurate.
Your sweat can be tested with a patch you put on your skin, but this is not a common test.
Does this test pose any risks?
Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore.
What might affect my test results?
A urine test can be falsely negative if the urine sample is cloudy or contains sediment. If someone tampers with the urine sample, the test may be inaccurate. Products can be added to urine to dilute it and throw off the test results.
If you are a drug user, you may not be able to produce enough saliva for a saliva sample. The tester may give you a piece of candy or gum to help you produce more saliva.
How do I get ready for this test?
No preparation is needed for urine, blood, or hair tests. Make sure your mouth is clean before you provide a saliva sample.
- Bass, Pat F. III, MD, MPH
- Stock, Christopher J, PharmD