Impact of saliva point-of-care testing on drug detection and clinical decision-making in the Emergency Department

Abstract

Recent advancements in point of care tests (POCT) have introduced test kits capable of detecting drugs of abuse (DOA) in saliva, offering a potential solution to the challenges associated with urine or blood collection. Previous studies have primarily focused on non-clinical settings, such as law enforcement, workplace drug testing, and monitoring in educational institutions and temporary housing for asylum seekers and homeless. This pilot study will be the first to assess the applicability of this POCT and is aimed to investigate whether these tests can serve as a reliable alternative to urine POCT in an emergency department setting.

This cross-sectional study included 60 adult patients at two EDs who underwent both urine and saliva DOA POCTs. Urine samples were analyzed using fluorescence immunoassay, while saliva samples were tested with the Dräger DrugTest 5000 device. Test results for both methods were compared to evaluate agreement between the two tests.

The saliva test demonstrated specificity up to 100%, but sensitivity varied significantly, ranging from 29% for benzodiazepines to 77% for methamphetamine. The positive predictive value (PPV) was near 100% for most substances, indicating reliable positive results. However, the negative predictive value (NPV) was lower for benzodiazepines and THC, suggesting the saliva test's limited ability to rule out drug use or because of their long-lasting metabolites in urine samples.

While saliva POCT provides rapid, non-invasive drug detection, its lower sensitivity and NPV limit its ability to fully replace urine testing in clinical settings. Saliva POCT is best suited for detecting recent drug use, especially in urgent clinical scenarios requiring fast decision-making.