Aim: To evaluate the use of preoperative tests in patients undergoing an elective surgery at the Dr. Rafael Ángel Calderón Guardia Hospital during 2009.

Methods: A cross-sectional observational analytical study was conducted. Two hundred and seventy two clinical histories, from patients who underwent surgery between 1 January 2009 and 3 June 2009, were analyzed. The analyzed variables were: age, coexisting morbidity prior to surgery, number and type of preoperative tests performed, missing and additional, and type of surgery performed. The number and type of preoperative tests required for each patient, depending on their morbidity, was decided according to the 2002 Guidelines of the American Society of Anesthesiologists (ASA).

Results: The mean of preoperative tests performed for each patient was 4.3 (SD + 2.1). According to morbidity, the tests prescribed by ASA were fully conducted in only 44.9% (CI: 95% 38.8-51.0) of the patients. The mean of missed preoperative tests per patient was 1.7 (SD + 1.1). Ninety three percent (CI: 95% 89.3-95.7) of patients underwent a mean of 2.5 (SD+1.6) additional preoperative tests. Of the additional preoperative tests performed, 9.5% showed abnormal results. Only 7.6% (CI: 95% 2.5-16.8) of the medical records with abnormal results, recorded actions towards correcting these abnormalities and surgery was cancelled only for 3% (CI: 95% 0.4-10.5) of these patients.

Conclusion: This study evidenced the inadequate use of preoperative tests, not only because they were not fully conducted in approximately 50% of patients, but also because a majority of them were requested a considerable amount of unjustified tests.