Pre-operative investigations: yield and conformity to national guidelines.

Routine ordering of pre-operative investigations yields a low true positive rate and is not cost effective. In this study, case notes of 251 adults who underwent elective surgery were reviewed. Pre-operative investigations were classified as 'indicated' or 'not indicated', based on the national guidelines. Only 56% of all tests done were indicated. The overall rates of expected and unexpected abnormal values from pre-operative blood investigations were 51.1% and 34.4% respectively. This study found that selective testing based on guidelines was beneficial. However, the results also suggest that the local guidelines need to be reviewed.