Abnormal routine pre-operative test results and their impact on anaesthetic management: An observational study

One of the reasons for continued routine pre-operative testing practice is the identification of hidden problems which may affect perioperative management. This study was aimed to assess the prevalence of abnormal test results, their impact on perioperative management and cost-effectiveness for detecting such abnormalities.

This observational study was conducted by screening the files of the patients attending pre-anaesthetic check-up during December 2016-January 2017. Patients' physical status, surgery grade, normal and abnormal test results and different impacts were noted and expressed in absolute numbers/percentage. Number needed to investigate (NNI) to detect a significant abnormality was calculated.

Data of 414 patients (46.3% male) with mean ± standard deviation age 43.78 ± 17.24 years and 58.65 ± 12.93 kg weight were analysed. Patients were mostly American Society of Anesthesiologists II and underwent National Institute of Clinical and Health Excellence Grade 3 surgeries. Totally, 345 (11.6%) test results were abnormal. Only 56 (16.2%) abnormalities had an impact in terms of referral, further investigations or delay. Twenty were significant in terms of changing perioperative anaesthetic management. Laboratory abnormalities with non-significant impact resulted in median delay of 3 days (range 1 to 12 days). The NNI for a significant impact and detecting new abnormality was 21 and 28, respectively.

Majority (57.2%) of the patients had at least one abnormal routine test result but only 1.8% abnormalities had significant impact. The NNI to find a significant impact or hidden comorbidity was more than 20.