Table 3.

Criterion Validation Data for the CPT Code-Based Classification Approach

Criterion Variable	CPT Code 99281	CPT Code 99282	CPT Code 99283	CPT Code 99284	CPT Code 99285
Percentage of all ED visits, %	4.3	14.9	31.4	27.4	21.9
Arrival by ambulance, %	10.3	11.5	18.2	26.7	35.2
Admitted to hospital, %	6.0	8.2	14.3	26.2	38.2
Length of stay, mean days if admitted	5.2	6.9	8.6	7.1	7.4
Medical charges, mean $ if admitted	7909	9844	11,070	11,341	13,175
All-cause NDI mortality by 2 years after     the baseline interview, % dead	9.3	3.3	6.9	12.9	22.3

Note: CPT = Current Procedural Terminology; ED = emergency department; NDI = National Death Index.