Inpatient Claim Diagnosis Reporting

10.2 - Inpatient Claim Diagnosis Reporting (Rev. 3081, Issued: 09-26-14, Effective: Upon Implementation of ICD-10, Implementation: Upon Implementation of ICD-10) On inpatient claims providers must report the principal diagnosis. The principal diagnosis is the condition established after study to be chiefly responsible for the admission. Even though another diagnosis may be more severe than the principal diagnosis, the principal diagnosis, as defined above, is entered. Entering any other diagnosis may result in incorrect assignment of a Medicare Severity - Diagnosis Related Group (MS- DRG) and an incorrect payment to a hospital under PPS. See Chapter 25, Completing and Processing the Form CMS-1450 Data Set, for instructions about completing the claim. Other diagnoses codes are required on inpatient claims and are used in determining the appropriate MS- DRG. The provider reports the full codes for up to twenty four additional conditions if they coexisted at the time of admission or developed subsequently, and which had an effect upon the treatment or the length of stay. The principal diagnosis should not under any circumstances be duplicated as an additional or secondary diagnosis. If the provider reports duplicate diagnoses they are eliminated in Medicare Code Editor (MCE) before GROUPER. The Admitting Diagnosis Code is required for inpatient hospital claims subject to A/B MAC (A) review. The admitting diagnosis is the condition identified by the physician at the time of the patient’s admission requiring hospitalization. For outpatient bills, the field defined as Patient’s Reason for Visit is not required by Medicare but may be used by providers for nonscheduled visits for outpatient bills.