Intra-observer variability in APACHE II scoring

Although the APACHE II score is the most widely used scoring system in inte nsive care units worldwide, its reliability and variability have not been e xtensively studied. Differences in case-mix may complicate comparison and i nterpretation of results. We hypothesised that a degree of variability migh t be inherent to use of the APACHE II scoring system, and decided to assess intra-observer variability in APACHE II scoring as a potential indicator o f inherent score variability. APACHE II scores were assessed twice from the charts of 11 patients by 14 physicians, with a time interval of 4 (range 3 .5-4.5) months between the two assessments. Intra-observer was found to be approximately 15 %. These findings are in agreement with previous observati ons regarding inter-observer variability in APACHE II scoring, and strongly suggest that there is an inherent score variability of about 15 %.