ICD-10 Codes for Hypertension (I10–I16)

The hypertension categories

ICD-10-CM organizes hypertension by what other organ it has started to affect. Start with whether the heart or kidneys are involved — that decides the category.

One thing that trips up coders from the ICD-9 era: ICD-10 has no “controlled/uncontrolled” hypertension codes (ICD-9 didn't either), and the old ICD-9 “benign” vs. “malignant” distinction was dropped.

The codes you'll use most

Need a code that isn't here? Search the full I10–I16 family in the lookup tool.

How to choose the right hypertension code

1. Is the heart involved?

If the record documents a qualifying heart condition with hypertension — heart failure (I50.-) or certain conditions in I51.- such as cardiomegaly or myocardial degeneration — use I11, not I10. Under the “with” convention, ICD-10 assumes the hypertension caused that heart condition, so no explicit causal statement is needed. When heart failure is present (I11.0), also code its type from I50.-. Important exception: coronary artery disease / atherosclerosis (I25.-) is not presumed related to hypertension — code it separately unless the provider documents a link.

2. Are the kidneys involved?

This one is special. Hypertension and chronic kidney disease are always coded as a combination (I12) — ICD-10 presumes they're related regardless of documentation. Pick the subcode by CKD stage, and also code the stage itself from N18.-.

3. Are both heart and kidney involved?

Use I13, which combines both. Choose the subcode by whether heart failure is present and by the CKD stage, and still add the I50.- and N18.- codes for specificity.

4. Is it a hypertensive crisis?

Code I16.0 for urgency or I16.1 for emergency, and also code the underlying hypertension (for example I10 or I11). I16 was added to ICD-10-CM in 2017, so older references may not show it.

Common hypertension coding mistakes

• Staying on I10 when the heart or kidneys are involved. Once heart disease/failure or CKD is documented, the code moves to I11, I12, or I13. Reporting I10 alone understates the condition.
• Forgetting the paired code. I11.0 needs the I50.- heart-failure code; I12 and I13 need the N18.- CKD stage. The combination code alone isn't complete.
• Hunting for “benign,” “malignant,” or “uncontrolled.” None exist in ICD-10. Document essential vs. secondary, organ involvement, and any crisis instead.
• Coding secondary hypertension as I10. When an underlying cause is documented (renal artery stenosis, an endocrine disorder), use I15.- — and per the guidelines, sequence the codes per the reason for the encounter.

A worked example

Don't overlook secondary hypertension

Most hypertension is essential (primary), but when the documentation points to an identifiable cause — renal artery stenosis, an endocrine disorder such as hyperaldosteronism, or a medication — it's secondary hypertension, coded from I15.-. ICD-10 asks you to code both the secondary hypertension and its underlying condition, sequenced according to the reason for the encounter. Reaching for I10 by reflex on a patient whose hypertension has a documented cause misses that specificity — and, in some payer models, the clinical picture that justifies the workup.

What the note needs to document

• Whether it's essential (primary) or secondary (and, if secondary, the underlying cause)
• Any heart involvement, and the type of heart failure if present
• Any chronic kidney disease, and its stage
• Hypertensive urgency or emergency if the visit involves a crisis

Frequently asked questions