CPT-4/HCPCS procedures code data elements (CPTn) contain the original values supplied by the data source, except that null values are set to blank. Codes are not validated and the information contained in them is not used for edit checking the consistency of patient's age and sex with procedures.
The original value of the primary CPT-4/HCPCS procedure (CPT1), whether blank or coded, is retained in the first position of the procedure vector. Starting at the first secondary procedure (CPT2), the procedures are shifted during HCUP processing to eliminate blank secondary procedures. For example, if CPT2 and CPT4 contain nonmissing procedures and CPT3 is blank, then the value of CPT4 is shifted into CPT3. Secondary procedures are never shifted into the primary position (CPT1).