To develop a self-test to measure clinical fitness to perform in surgical residents, with alcohol-induced impairment as reference. Observational, exploratory study to evaluate night shift-induced impaired performance in surgical residents followed by a randomized blinded, placebo-controlled, crossover study to evaluate impaired performance as a result of ethanol intoxication. Impairment was quantified using the Mini-NeuroCart, a psychomotor and cognitive test battery for assessment of subjective and objective measures of alertness, concentration, eye-hand coordination, mood, and self-assessed ability to perform. Surgical performance was tested in the randomized study with a laparoscopy surgical trainer. Level-I trauma hospital and a clinical research unit. Surgical residents (n = 12 for the observational study, n = 18 for the randomized study). High alcohol levels (0.6gL-1) impaired adaptive tracking, reduced objective and subjective alertness, and increased slowness. Moreover, laparoscopy depth perception was impaired in the 0.6gL-1 group. No significant within-subject correlation between subjective and objective measures of alertness was found. Performance of postcall surgeons was similar to, or even worse than, the performance of intoxicated surgeons. The Mini-NeuroCart detected ethanol-induced performance effects that were similar to the effects of working a 14-hour night shift. Social (ethanol), personal (mood), and professional (laparoscopic skills) standards of fitness can in this manner be related to accepted deleterious effects of alcohol. The Mini-NeuroCart is, therefore, a potential noninvasive test for assessing "fitntness to perform" in healthcare professionals.