ICD-10 Codes for Hypertension: The Full Guide

The ICD-10 code for hypertension is one you have typed more times than you can count: I10. Yet hypertension coding is more layered than that single code suggests. The moment the heart or kidneys get involved, or a patient hits a crisis, the correct code shifts, and picking the wrong one affects claims, quality measures, and the patient’s record. This guide lays out the full hypertension code family in plain English, so you can code it right the first time.

Quick Answer

The ICD-10-CM code for hypertension is I10, used for essential (primary) hypertension. ICD-10 no longer separates benign, malignant, or controlled versus uncontrolled hypertension, so most cases use I10. Related conditions use the I11 through I16 codes, depending on heart or kidney involvement.

In this guide:

• What Is the ICD-10 Code for Hypertension?
• The Full Hypertension Code Family (I10–I16)
• I11: Hypertensive Heart Disease
• I12: Hypertensive Chronic Kidney Disease
• I13: Hypertensive Heart and Kidney Disease
• I15: Secondary Hypertension
• I16: Hypertensive Crisis
• Special Cases: Pulmonary, Pregnancy, Resistant
• Common Coding Mistakes to Avoid

What Is the ICD-10 Code for Hypertension?

The ICD-10-CM code for hypertension is I10, defined as essential (primary) hypertension. This is the code you use for the vast majority of patients: high blood pressure with no identifiable secondary cause and no documented heart or kidney complication. It covers what older records called benign, malignant, systemic, primary, or unspecified hypertension.

One of the biggest shifts from ICD-9 is what I10 absorbed. ICD-9 split hypertension into benign (401.1), malignant (401.0), and unspecified (401.9). ICD-10 collapsed all three into a single code. There is also no separate code for “controlled” or “uncontrolled” hypertension. You document the clinical detail in the note, but the code stays I10.

The Full Hypertension Code Family (I10–I16)

Hypertension lives in the I10–I16 block. The right code depends on whether the heart, the kidneys, or both are affected, and whether the patient is in crisis. Here is the full family at a glance.

A key rule runs through this family: when the heart or kidneys are involved, ICD-10 assumes a causal link and wants a combination code (I11, I12, or I13) rather than I10 plus a separate code. You then add codes to specify the heart failure or the CKD stage.

I11: Hypertensive Heart Disease

Use the I11 family when a provider documents heart disease as related to hypertension. It has two options:

• I11.0 — Hypertensive heart disease with heart failure
• I11.9 — Hypertensive heart disease without heart failure

With I11.0, add a second code from the I50 category to identify the type of heart failure, such as systolic, diastolic, or combined, and whether it is acute or chronic. The heart failure code never stands alone here; it partners with the hypertensive code.

I12: Hypertensive Chronic Kidney Disease

Use I12 when hypertension and chronic kidney disease are both present. ICD-10 presumes a link between the two, so you code the combination even if the provider does not explicitly connect them.

• I12.0 — With stage 5 CKD or end-stage renal disease
• I12.9 — With stage 1 through 4 CKD, or unspecified CKD

Always add the matching N18 code to specify the CKD stage (for example N18.30 for stage 3 unspecified, or N18.6 for ESRD). The stage code sits second, right after the hypertensive code.

I13: Hypertensive Heart and Kidney Disease

When the heart and the kidneys are both involved, I13 combines them into one code. This is the most detailed group, and the right choice depends on heart failure status and CKD stage.

As with the other combination codes, add the I50 heart failure code and the N18 CKD stage code to complete the picture.

I15: Secondary Hypertension

Secondary hypertension is high blood pressure caused by an identifiable underlying condition. When the cause is known, code both the underlying condition and the secondary hypertension.

• I15.0 — Renovascular hypertension
• I15.1 — Hypertension secondary to other renal disorders
• I15.2 — Hypertension secondary to endocrine disorders
• I15.8 — Other secondary hypertension
• I15.9 — Secondary hypertension, unspecified

I16: Hypertensive Crisis

The I16 category, added in FY2018, finally gave coders specific codes for a hypertensive crisis. Sequence the crisis code first, then also assign the underlying hypertension code (such as I10 or I11).

• I16.0 — Hypertensive urgency
• I16.1 — Hypertensive emergency
• I16.9 — Hypertensive crisis, unspecified

Special Cases: Pulmonary, Pregnancy, and Resistant

Not every “hypertension” belongs in the I10–I16 block:

• Pulmonary hypertension is coded in the I27 family, not with systemic hypertension. Primary pulmonary hypertension is I27.0, and the I27.2- subcategories cover secondary types.
• Hypertension in pregnancy uses the O10–O16 codes, including pre-existing hypertension (O10), gestational hypertension (O13), and pre-eclampsia (O14).
• Resistant hypertension now has its own code, I1A.0, added in FY2023. Assign it in addition to the underlying hypertension code.

For the full clinical picture behind these codes, see our ultimate guide to hypertension, which explains the stages, causes, and treatment in depth.

Common Coding Mistakes to Avoid

• Coding “malignant hypertension.” There is no malignant code in ICD-10. Use I10, or I16.1 if it is a hypertensive emergency.
• Looking for an “uncontrolled” code. ICD-10 does not distinguish controlled from uncontrolled. Both are I10.
• Coding I10 plus a separate CKD code. When hypertension and CKD coexist, use the I12 or I13 combination code instead.
• Forgetting the secondary codes. I11, I12, and I13 usually require an added I50 or N18 code.
• Placing pulmonary hypertension in I10. It belongs in the I27 family.

Key Takeaways

• The ICD-10 code for hypertension is I10 (essential/primary).
• ICD-10 dropped the benign, malignant, and controlled versus uncontrolled distinctions.
• Heart involvement uses I11, kidney uses I12, both use I13.
• Secondary hypertension is I15; a hypertensive crisis is I16.
• Pulmonary hypertension (I27) and pregnancy hypertension (O10–O16) are coded separately.

The Verdict

For a straightforward patient, the ICD-10 code for hypertension is simply I10. The skill is knowing when to leave it behind: reach for I11, I12, or I13 the moment the heart or kidneys are documented, add the required heart failure or CKD stage codes, and use I16 for a crisis. Master that logic and hypertension coding becomes one of the cleaner corners of ICD-10.