Inpatient Claim Diagnosis

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.

Other diagnoses codes are required on inpatient claims and are used in determining the appropriate MS-DRG.

The provider reports the full codes 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 Admitting Diagnosis Code is required for inpatient hospital claims.  

The admitting diagnosis is the condition identified by the physician at the time of the patient’s admission requiring hospitalization. 

The Official ICD-10-CM and ICD-10-PCS Coding Guidelines can be found with the annual ICD-10-CM and ICD-10-PCS updates.