Kim E, et al. - Through a cross-sectional observational study of 168 cases who received lidocaine as part of their regular care, the researchers intended to assess whether lidocaine exposure from regular medical procedures could lead to false positives on a commercially available cocaine immunoassay urine drug screen (UDS) since it was claimed by the people who were examined positive for cocaine. One hundred and twenty-one samples positive for lidocaine out of 168 were included for analysis. Out of 121, 114 were also positive for monoethylglycinexylidide (MEGX). However, out of 121, none were observed as positive for cocaine/benzoylecgonine on the UDS, 0–3.7% for the full sample and 0–3.9% for the 114 who were examined positive for MEGX. Hence, on standard cocaine urine immunoassays, no signs could be ascertained that lidocaine or norlidocaine were competent in generating false positive results.