Does on-site urine toxicology screening have an added diagnostic value in psychiatric referrals in an emergency...

The objective was to examine the added diagnostic value of on-site urine toxicology screening (UTS) in the routine assessment of psychiatric patients in an urban emergency setting.

A naturalistic two-step prospective cohort study design was used enrolling all emergency room (ER) patients referred for psychiatric consultation. In two consecutive cohorts, diagnosis of drug use was assessed based on routine psychiatric interview without (n=64) and with on-site UTS (ACON) (n=56). In both cohorts, drug use was also assessed by post hoc laboratory-based urine immunoassay (Triage) as the gold standard.

Sensitivity and specificity of diagnosis of drug use based on psychiatric interview only varied (0.75 and 1 in the interview-based cohort; 0.5 and 0.75 in the interview+on-site UTS cohort). The sensitivity and specificity of on-site UTS were 0.93 and 0.97.

In an ER setting, the validity of the diagnosis of drug abuse exclusively based on psychiatric interview is low. The use of on-site UTS provides accurate data on drug use and is more practical as compared to post hoc laboratory assessment. On-site UTS has an added diagnostic value of drug use with high sensitivity and specificity.