Format/length: an6
HES item: DIAG_1 for Patient Diagnosis
CENDIAG1 for Patient Diagnosis on Psychiatric Census Date for the Psychiatric Census Record: Additional Data Fields
National Codes:
Default Codes:

See DIAGNOSTIC CODING for details on coding and PRIMARY DIAGNOSIS for the standardised definition of primary diagnosis. 

This data element is also known by these names:

Context Alias
plural PRIMARY (ICD-10)