Evaluation of intoxication in patients with acute impaired consciousness using rapid urine test tape; a diagnostic accuracy study

 Determining the exact underlying etiology of loss of consciousness (LOC) can become a real challenge for physicians due to the broadness of differential diagnoses. The current study aimed to assess the accuracy of a commercially available strip for urine drug screening, in patients presenting with LOC. 

 One hundred fifty patients with LOC were enrolled in the current cross-sectional study. The diagnostic accuracy of a multidrug urinary strip rapid test was evaluated in comparison to blood analysis as the reference test, and the screening performance characteristics of the rapid test for each substance were estimated. 

 The average age of patients was 46.21±18.59 years (72.67% male). The most frequent false positive results of the test were related to Benzodiazepine (21.5%), Methamphetamine (7.5%), and Tramadol (5.4%), respectively. The screening performance characteristics of the test tape were the best in detection of Amitriptyline with 100.0% (95% CI: 30.99 – 100.0) sensitivity, Cocaine with 100.0% (95% CI: 5.46 – 100.0) sensitivity, and Methadone with 91.54% (95% CI: 81.88 – 96.51) sensitivity, respectively. 

 The current study reveals that employing a urinary strip test for detecting drug intoxication in the setting of emergency department can lead to significant false positive and negative results. Accordingly, relying on a urine drug screen to determine the underlying etiology of LOC should be done with caution.