Toxicology: Oral Fluid Drug Testing

The analysis of drugs of abuse in oral fluid is becoming more widely used and accepted across a number of testing disciplines, particularly because it is so simple to collect in comparison to urine. Oral fluid testing is now practiced in a variety of settings such as the workplace, drug-treatment centres, health assessments, and in the legal arena.

Oral fluid reflects drug use for a relatively short period, reflecting the use occurred hours before sample collection.

The use of oral fluid is ideal for example when assessing recent drug use in drug-treatment centres or impairment in the workplace, because when drugs are present in oral fluid samples, they actually reflect the use of drugs in the last 24 hours, which is very useful in post-accident or post-incident investigation in the workplace.

Both common drugs of abuse and prescribed drugs are detectable in oral fluid.


The convenience and ease in collection of oral fluid under observed conditions, together with significant advances in analytical technology has advanced oral fluid testing for drugs of abuse as an alternative to urine testing.

Drug testing with other type of samples

The use of biological samples is universally accepted for the diagnosis of drug use. In the past, blood or urine were most commonly used in this detection. Samples of blood are considered invasive and are less commonly used due to limitations regarding the collection, since phlebotomists must take it.

In the early days of the analysis of drugs, urine was the only choice because of the relatively large amount of sample obtained and the concentrations detectable by the technology in use then. Whilst urine remains the most commonly used sample for the same reasons, which make the laboratory analysis easier, its collection is considered “invasive” or “undignified”.

Hair samples are ideal for the detection of drugs over a longer period, but does not detect drugs used in the  5-6 days before collection of the hair sample.

Analysis of hair provides a much longer window of detection, typically 1 to 3 months as drugs and other substances remain fixed and trapped in the hair indefinitely after they are incorporated in the hair after drug use.

Posted in Oral fluid testing, Workplace Drug Testing Tagged with: , , , ,