Abstract Purpose The purpose of this study was to determine the minimal detectable change (MDC) and responsiveness of the Perme Score when used in the adult intensive care unit (ICU) population. Methods This is a prospective longitudinal study which was conducted from November 2016 to July 2017 in Cali, Colombia. Four physical therapists with observer and evaluator roles, applied the Perme Score upon ICU admission and discharge. The Consensus‐based Standards for the Selection of Health Measurement Instruments Protocol standards to analyze sensitivity to change were used. The sample size was defined considering the lowest concordance proportion reported (68.6%), and a Kappa Index of 0.2784 or higher to guarantee an adequate n , and a 95% reliability level. Results One hundred and forty‐two patients were enrolled in the study. There were 51.4% men with an average age of 58 ± 17 years. Invasive mechanical ventilation was employed in 42.0% of the patients. The MDC for the Perme Score was 1.36, and 80% of patients demonstrated higher or equal values, detecting a significant difference in the type of weaning and the length of stay in the ICU ( p < 0.005). Conclusions The Perme Score has an MDC of 1.36 points and shows evidence of being sensitive to change. Therefore, the findings validate the responsiveness of the instrument.