1. Month, day, and year a patient receives a medical service. Dates of service are inserted in Block 24A Lines 1 through 6 of the CMS-1500 insurance claim form. Service date is inserted in Field 45 of the Uniform Bill (UB-04) inpatient hospital billing claim form. The electronic version requires an eight-character date listing year, month, and day: 20XX0328. 2. For health insurance, the effective date of membership. 3. For employment, the effective date of full-time employment.