Table 3.

Identified and Confirmed Nonmelanoma Skin Cancer Cases and Positive Predictive Values, by Algorithm, 2007 HMO Health Plan Enrollee Claims Data, Henry Ford Health System, Detroit, Michigan

Identification Algorithm	No. of Identified Cases	No. of Confirmed True Cases	PPV	95% CI
ICD-9-CM code alone	1,110	1,071	0.965	0.954, 0.976
CPT code alone	1,079	1,061	0.983	0.976, 0.991
Both ICD-9-CM and CPT codes	1,073	1,059	0.987	0.980, 0.994

Abbreviations: CI, confidence interval; CPT, Current Procedural Terminology; HMO, health maintenance organization; ICD-9-CM, International Classification of Diseases, Ninth Revision, Clinical Modification; PPV, positive predictive value.