Metabolization of cocaine in the body occurs so quickly that urine tests taken just a short six hours following ingestion of cocaine rarely shows evidence of cocaine use. What a cocaine urine test actually screens for is benzoylecgonine (BE), the primary metabolite of cocaine that remains in the body for an extended period. Other metabolites left behind by cocaine include ecgonine methyl ester (EME), m-hydroxycocaine, norcocaine and p-hydroxybenzoylecgonine (pOHBE).
What is Considered a Positive Urine Test for Cocaine?
Most employers use cutoff levels established by the National Institute of Drug Abuse (NIDA) to determine whether a potential employee has been using cocaine. Urine levels at or exceeding 300 nanograms of BE per milliliter of urine are considered positive. However, levels of cocaine metabolites in urine can vary individually depending on if the test was done in the morning or later in the day.
Samples taken from a person’s first urine void of the day almost always yield higher concentrations of cocaine metabolites than urine tested later in the day. Additionally, employers are well aware of methods people use to dilute their urine in an attempt to pass a drug screening. Assuring accurately representative specimens means employers must implement random, unannounced cocaine/drug testing in the workplace.
Variables Affecting Cocaine’s Ability to Remain in Your System
Cocaine comes in a wide variety of purities and forms, which influences the length of time it remains in the body. In addition, how much cocaine is used, how frequently it is used and how it is ingested (snorting, injecting, smoking, etc) directly determines how quickly cocaine is assimilated, metabolized and eliminated through urine.
Although injecting cocaine provides the fastest “high” and therefore, the quickest way to eliminate it from the body, its main metabolite benzoylecgonine will still be detectable in urine for as long as several weeks.
Combining cocaine and other drugs may also lengthen the life of BE and other cocaine metabolites. For example, when alcohol and cocaine are used simultaneously, another metabolite called coca-ethylene is created that is harder to expel than BE.
In addition, cocaine metabolites that are not eliminated through urine are stored in fat cells. Consequently, people with body mass indexes indicating they are overweight or obese may retain higher amounts of metabolites for longer periods of time than their thinner constituents.
How Cocaine is Metabolized
Created in the liver as a byproduct of metabolized cocaine, benzoylecgonine is generated by enzymes called carboxylesterases and eventually excreted in the user’s urine. By themselves, cocaine alkaloids have extremely short half-lives that are undetectable within 24 to 48 hours. However, BE and other cocaine metabolites can remain in the body for several weeks or even months, depending how much cocaine was used, the individual’s unique biological characteristics and type of drug screening employed.
Regardless of how cocaine is consumed, it can be detected in saliva and blood for up to 72 hours. Testing of cocaine users’ sweat has found evidence of metabolites several weeks after last using cocaine. Even if a user has abstained from cocaine ingestion for two, three or four years, their hair follicles may still retain metabolite deposits.