Pitfalls in the role of standardized preadmission laboratory screening for ambulatory surgery

We conducted a one-year retrospective analysis to determine the effect of a standardized preadmission screening (PAS) program on the cancellation rate of ambulatory surgery. Patients were divided into two groups. Group One patients had selective PAS lab work based on history and physical examination. Group Two patients underwent a standardized PAS consisting of history, physical examination, biochemical profile, complete blood count, and urinalysis. Patients in both groups received a prothrombin/partial thromboplastin time (PT/PTT) if one anticoagulation therapy, an electrocardiogram (EKG) with age greater than 40 years, and a chest X ray with age greater than 50 years. We found that the frequency of surgery cancellation before and after instituting a standardized PAS remained the same (6.9% vs 6.4%); furthermore, only 38.5 per cent of the cancellations in Group One and 16.4 per cent in Group Two were due to laboratory, EKG, or chest X-ray results. The rest were due to intercurrent illness, scheduling conflicts, and other uncontrollable factors. A closer analysis of Group Two shows that of 4,058 standardized preadmission screens performed, 4,015 (99%) were normal; only 43 (1%) had abnormal results that led to cancellation of ambulatory surgery. Similarly, 99.93 per cent of all EKGs and 99.97 per cent of all chest X-rays performed in both groups were normal, having no influence on operational performance or patient management. We suggest that selective use of laboratory and diagnostic studies, in conjunction with a thorough history and physical examination, is as effective as a standardized PAS in identifying patients at risk for ambulatory surgery.(ABSTRACT TRUNCATED AT 250 WORDS)