2006 ICD-9-CM Volume 1 Diagnosis Codes Home > Diseases Of The Circulatory System 390-459 > Hypertensive Disease 401-405 > Essential Hypertension 401.* > 2006 ICD-9-CM Diagnosis 401.1 Benign essential hypertension View the most recent version of ICD-9-CM 401.1 401.1 is a specific code that can be used to specify a diagnosis View the ICD-9-CM Volume 1 401.* hierarchy