I10Essential (primary) hypertension

I10 is the ICD-10-CM diagnosis code for essential (primary) hypertension. It belongs to block I10-I1A (hypertensive diseases) and chapter 9 (diseases of the circulatory system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Don't report I10 together with the conditions in its Excludes1 note: hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16).

The conditions in its Excludes2 note aren't part of I10, but may be coded alongside it if the patient has both: essential (primary) hypertension involving vessels of brain (I60-I69) and essential (primary) hypertension involving vessels of eye (H35.0-).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 304 (Hypertension with MCC, relative weight 1.2011) and DRG 305 (Hypertension without MCC, relative weight 0.7581), in MDC 05 (Diseases and Disorders of the Circulatory System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

When it is the principal diagnosis, Medicare considers it a questionable reason for an inpatient admission, so claims may be reviewed.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 401.0 (malignant essential hypertension), 401.1 (benign essential hypertension) and 401.9 (unspecified essential hypertension).