Safety Bulletins

FAQ. Urine vs Oral Fluid Testing

What are the main differences between the two testing methodologies? Oral fluid testing (OFT) has a shorter window of detection, typically hours as compared to urine in which use may be detected after several days. OFT is therefore seen to align more closely with the very recent use of drugs, however, it may also fail to detect drug use during a withdrawal (crashing) when behavioural (safety) risks are significant. OFT may afford sample collection advantages including less invasive collection and no need for special collection facilities.

Is urine testing easy to cheat? Urine testing has several time-tested safeguards e.g. a urine temperature check and abnormal creatinine levels. The primary method used to cheat is to swap-in a clean sample, however, such cheating needs to be stealthy, given the observation requirements laid upon the testing agent under the standard. Notwithstanding, some have been successful at cheating the urine test.

Is OFT easy to cheat? Many consider this is one of OFTs advantages! Nevertheless, it must be noted that oral fluid may be diluted, corrupted or completely neutralised by (1) brushing the mouth thoroughly with a toothbrush, or (2) using an acidic mouthwash, or (3) using a detox kit. In terms of Cannabis use, a person ingesting it e.g. in a cookie will not be detected in an OFT irrespective of when the test is conducted.

Will OFT provide a cost benefit? AS/NZS 4760:2019 requires that a not negative donor sample is followed by a second OFT swab and then both must be sent to the laboratory (as the A and B samples) for confirmation. Currently there are no accredited laboratories here in NZ so the samples must be confirmed in Melbourne. The cost to courier currently is $AU 600 (not including the cost of analysis). Two NZ laboratories are currently getting ready to provide analysis, however, it seems that the overall costs will be around the same if not a bit more than for urine.

Conclusion: We can't wait for OFT to come in. Most, like PF Olsen, have now experienced one or two presentations by toxicologists and the mood has changed to a watching brief. PF Olsen has not ruled out OFT, but there is more work to be done.

View this article in Safety Bulletin 118