Beginning in the fourth quarter of 2015, International Classification of Diseases, Tenth Revision, Procedure Coding System (ICD-10-PCS) procedures reported on HCUP records are stored in the data element I10_PRn. In data prior to the fourth quarter of 2015, International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) procedures reported on HCUP records are stored in the data element PRn.

In the HCUP databases, ICD-10-PCS procedures are represented by alphanumeric codes with a maximum length of 7 characters. The HCUP data elements for ICD-10-PCS procedures are length 7 and may use the letter Z as a placeholder. The codes are left-justified in the HCUP databases. For example, consider the procedure code BB12ZZZ for fluoroscopy of the right lung. There are no decimals in ICD-10-PCS procedure codes.

The original value of the ICD-10-PCS first listed procedure (I10_PR1), whether blank or coded, is retained in the first position of the procedure vector. Starting at the first secondary procedure (I10_PR2), the procedures are shifted during HCUP processing to eliminate blank secondary procedures. For example, if I10_PR2 and I10_PR4 contain nonmissing procedures and I10_PR3 is blank, then the value of I10_PR4 is shifted into I10_PR3. Secondary procedures are never shifted into the first-listed position (I10_PR1).

Procedures are compared to a list of ICD-10-PCS codes valid for the discharge date. Anticipation of or lags in response to official ICD-10-PCS coding changes are permitted for discharges occurring within a window of time (six months before and six months after) around the official ICD-9-CM coding changes (usually October 1). If the procedure contains intermittent blank characters or is zero filled, then the procedure will be considered invalid.

Procedures are compared to the sex of the patient (edit check EPR03) and the patient's age (edit check EAGE05) for checking the internal consistency of the record.

Invalid and inconsistent codes are handled in the following way.

Shriner's hospitals do not report diagnoses, procedures or total charges.

In 2018 Massachusetts SID, a small number of records have blank values for I10_PR2 and I10_PR3, but coded procedures in position 4+. This caused the records to have a value of I10_NPR that is shorter than the true length of the array.

Beginning in 2008, New York suppressed the identifier for the hospital (DSHOSPID) on records with an indication of induced abortion. These records are retained in the HCUP SID with the DSHOSPID set to "BLNK".

To comply with statutory requirements, Wisconsin modified diagnosis and procedure codes that explicitly referenced induced termination of pregnancy to eliminate distinctions between induced and spontaneous termination. Beginning Q4 2015, the following codes were modified:

• Diagnosis Z33.2 was changed to Z31.9,
• Diagnoses O04x and O07x were changed to O03.9,
• Procedure 10A07ZZ was changed to 10D17ZZ,
• Procedure 10A08ZZ was changed to 10D18ZZ,
• Procedure 10A07ZZ was changed to 10D17ZZ,
• Procedure 10A08ZZ was changed to 10D18ZZ,
• Procedure 10A07ZW was changed to 0UCB7ZZ,
• Procedure 10A00ZZ was changed to 10D00Z0,
• Procedure 10A03ZZ was changed to 0UC93ZZ,
• Procedure 10A04ZZ was changed to 0UC94ZZ,
• Procedure 10A07ZX was changed to 3E0P7GC.