DRG GROUPER Program

(Rev. 3030, Issued: 08-22-14, Effective: ASC X12: January 1, 2012, ICD-10: Upon Implementation of ICD-10, Implementation: ICD-10: Upon Implementation of ICD- 10, ASC X12: September, 23 2014)

The A/B MAC (A) pays for inpatient hospital services on the basis of a rate per discharge that varies according to the MS-DRG to which a beneficiary's stay is assigned. Each MSDRG represents the average resources required to care for a case in that particular MSDRG relative to the national average of resources consumed per case. The MS-DRG weights used to calculate payment are in the Pricer DRGX file. 

The A/B MAC (A) uses the GROUPER program to assign the MS-DRG number. GROUPER determines the MS-DRG from data elements reported by the hospital. This applies to all inpatient discharge/transfer bills received from both PPS and non-PPS facilities, including those from waiver States, long-term care hospitals, and excluded units. T

he Pricer (PPSMAIN) driver program calls the correct fiscal year GROUPER based upon the discharge date. If the A/B MAC (A) or shared system writes its own driver program, it must access the GROUPER for the correct FY based on discharge date. GROUPER does not determine the MS-DRG price. GROUPER input/output are specified below. The A/B MAC (A) determines the best place in its total system to place the GROUPER program.

Grouper requires the following items:

1. Principal and up to 24 other diagnoses 

2. Principal and up to 24 additional procedures 

3. Age at last birthday at admission 

4. Sex (1=male and 2=female) 

5. Discharge destination (patient status code from the claim)

The claim sex coding is M for male and F for female while GROUPER is l for male and 2 for female. Discharge destination codes are similar to claim definitions for patient status except codes 20-29 are summarized as 20. The A/B MAC (A) calculates age at admission. GROUPER needs age rather than date of birth.

Grouper responds with the following information: 

1. Major diagnostic category 

2. MS-DRG number 

3. Grouper return code (a one position code indicating the action taken by the program) 

4. Procedure code used in determining the MS-DRG 

5. Diagnosis code used in determining the MS-DRG 

6. Secondary diagnosis code used in determining the MS-DRG, if applicable