Table 2.

Prevalence of testing in patients seeing physicians for pre-operative visits or general medical exams in the U.S., 1997-2010

	Pre-operative visits			General medical exams
Pre-operative tests	Unweighted No.	Weighted Annual No.	Percent, %	Unweighted No.	Weighted Annual No.	Percent, %	OR for Difference	95% CI	P value
Plain radiography	953	1,060,083	10.3	1,492	2,556,729	5.2	2.11	1.76 to 2.54	<0.001
Hematocrit	322	665,287	7.80	1,589	6,079,908	12.5	0.59	0.45 to 0.77	<0.001
Urinalysis	798	1,027,702	10.0	5,714	10,686,372	21.6	0.40	0.34 to 0.48	<0.001
ECG	1,300	1,638,962	16.0	2,126	5,178,623	10.5	1.63	1.38 to 1.92	<0.001
Cardiac stress test	171	171,022	1.70	231	393,508	0.8	2.11	1.44 to 3.10	<0.001
Any test*	2,370	2,723,526	26.5	7,840	14,552,887	29.4	0.87	0.76 to 0.99	0.035
Any test†	1,314	2,517,477	29.4	5,298	17,012,107	35.0	0.77	0.64 to 0.93	0.007

Abbreviations: CI, confidence interval; ECG, electrocardiography; No., number; OR, odds ratio

^*Does not include hematocrit blood tests, which were available from 1997-2004 only

^†Includes hematocrit; therefore time period limited to 1997-2004