For 1995-1996 data only, some discharges have NPR greater than 0, and yet all procedure codes are missing. This is due to constraints of the HCUP processor in handling CPT and HCPCS codes. Pennsylvania reports ICD-9-CM procedure codes on most of their discharges, but some use CPT and HCPCS procedure codes. CPT and HCPCS procedure codes could not be retained in the HCUP data because they are 5 characters and the HCUP procedure fields are 4 characters in length. Discharges with CPT and HCPCS procedure codes were processed by HCUP as follows:
- PRSYS identifies the procedure coding system as CPT or HCPCS.
- NPR is the number of non-missing CPT or HCPCS procedure codes supplied by Pennsylvania.
- The HCUP procedure codes are set to missing (PRn = blank).
In other years, CPT and HCPCS codes are either masked or were handled differently in other years. See the Pennsylvania note on procedures (PRn) for specific details.