Table 4. Percentage of abnormal preoperative screening tests, according to patients’ ages among 991 patients operated in São Paulo, Brazil.

Age (years)	Hematocrit (%)	Blood urea (mg/dl)	Serum creatinine (mg/dl)	Abnormal electrocardiogram	Abnormal chest X-ray
40-60	37.4	16.2	10.0	43.1	33.3
> 60	43.4*	31.1*	15.0*	58.6*	45.8*

^* p < 0.05 compared to percentage obtained for patients aged 40-60 years.