ICD-10 Code for Hypertension (I10): The Full Code Family, With CKD Stages

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, diabetes enters the picture, or a patient arrives in 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, including the chronic kidney disease stage codes and the combinations coders search for most, so you can code it right the first time.

Quick Answer

The ICD-10-CM code for hypertension is I10, essential (primary) hypertension. ICD-10 does not separate benign, malignant, accelerated, controlled or uncontrolled hypertension, and stage 1 and stage 2 hypertension are both I10. When hypertension and chronic kidney disease (CKD) coexist, use I12 plus an N18 stage code; with heart failure or the listed heart conditions, use I11; with both, use I13. Secondary hypertension is I15, a hypertensive crisis is I16, and resistant hypertension adds I1A.0. A high reading without a diagnosis of hypertension is R03.0.

In this guide:

• What Is the ICD-10 Code for Hypertension?
• The Full Hypertension Code Family (I10 to I16)
• I11: Hypertensive Heart Disease
• I12: Hypertensive Chronic Kidney Disease, With CKD Stage Codes
• I13: Hypertensive Heart and Kidney Disease
• Hypertension With Diabetes
• I15: Secondary Hypertension
• I16: Hypertensive Crisis
• Elevated Blood Pressure Without Hypertension: R03.0
• 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, essential (primary) hypertension. It is the code for the vast majority of patients: high blood pressure with no identified secondary cause and no documented heart or kidney complication. It covers what older records called benign, malignant, systemic, primary, chronic or unspecified hypertension.

One of the biggest shifts from ICD-9 is what I10 absorbed. ICD-9 split hypertension into malignant (401.0), benign (401.1) and unspecified (401.9). ICD-10 collapsed all three into a single code. These all map to I10 as well:

• Controlled or uncontrolled hypertension: there is no separate code. Document the control status in the note.
• Stage 1 or stage 2 hypertension (HTN stage 2): ICD-10 has no stage codes for hypertension.
• Accelerated or malignant hypertension: I10, unless documented as a hypertensive emergency or urgency (I16).
• Hypertension controlled on medication: still current hypertension, so I10, not a history code.

The Full Hypertension Code Family (I10 to I16)

Hypertension lives in the I10 to I16 block, plus I1A for resistant hypertension. The right code depends on whether the heart, the kidneys or both are affected, whether there is a known cause, and whether the patient is in crisis.

A key rule runs through this family. The ICD-10-CM Official Guidelines presume a cause-and-effect link between hypertension and heart failure, certain heart conditions, and chronic kidney disease, even when the provider does not write “due to”. So instead of I10 plus a separate code, you use a combination code (I11, I12 or I13), then add codes for the heart failure type or the CKD stage. The only exception is when the provider documents that the conditions are unrelated.

I11: Hypertensive Heart Disease

Use I11 when hypertension coexists with heart failure (I50.-) or with the heart conditions in I51.4 to I51.7, I51.89 and I51.9, such as myocarditis, cardiomegaly or unspecified heart disease. These links are presumed.

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

With I11.0, add a code from category I50 to identify the type of heart failure: systolic, diastolic or combined, and acute, chronic or acute on chronic. The heart failure code does not stand alone here; it partners with the hypertensive code.

Coronary artery disease is different. CAD (I25.-) is not on the presumed list, so “CAD with HTN” is coded separately, typically I25.10 (atherosclerotic heart disease of native coronary artery without angina) plus I10, unless the provider links them.

I12: Hypertensive Chronic Kidney Disease, With CKD Stage Codes

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

• I12.0: Hypertensive CKD with stage 5 CKD or end-stage renal disease (ESRD)
• I12.9: Hypertensive CKD with stage 1 through 4 CKD, or unspecified CKD

Always add the N18 code for the CKD stage. Stage 3 was split into 3a and 3b from FY2021, so check the documentation for the subtype:

So “hypertension with CKD stage 4” is I12.9 plus N18.4, and “hypertension with CKD stage 3b” is I12.9 plus N18.32. For a patient with ESRD on dialysis, code I12.0, N18.6 and Z99.2 (dependence on renal dialysis). Acute kidney injury (N17.-) is not chronic kidney disease and does not trigger I12.

I13: Hypertensive Heart and Kidney Disease

When the heart and the kidneys are both involved, I13 combines them into one code. 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 stage code. For example, hypertensive heart and kidney disease with chronic diastolic heart failure and CKD stage 3a is I13.0, I50.32 and N18.31.

Hypertension With Diabetes

Diabetes, hypertension and CKD often appear together, and the rules differ for each pair:

• Diabetes and CKD: the guidelines’ “with” convention presumes a link, so type 2 diabetes with CKD is E11.22, plus the N18 stage code.
• Diabetes, hypertension and CKD: code all three relationships: E11.22, I12.9 (or I12.0 for stage 5 or ESRD) and the N18 stage code.
• Diabetes and hypertension without CKD: there is no presumed link and no combination code. Code the diabetes (for example E11.9) and I10 separately. Only if the provider documents that the hypertension is caused by the diabetes is it treated as a diabetic complication, typically E11.59 (type 2 diabetes with other circulatory complications) with I10.

I15: Secondary Hypertension

Secondary hypertension is high blood pressure caused by an identified underlying condition, such as renal artery stenosis or an adrenal tumor. Code both the underlying condition and the secondary hypertension; sequencing depends on the reason for the encounter.

• 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 gives specific codes for a documented hypertensive crisis:

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

Also code the underlying hypertensive disease (I10 to I15). The guidelines base the sequencing on the reason for the encounter rather than always putting I16 first.

Elevated Blood Pressure Without Hypertension: R03.0

When a patient has a high reading but the provider has not diagnosed hypertension, use R03.0, elevated blood-pressure reading without diagnosis of hypertension. This also covers white-coat hypertension, where readings are high in the clinic but normal elsewhere. Do not assign I10 from a single high reading.

R03.0 matters because so much hypertension goes undiagnosed. In the US national health survey for 2021 to 2023, 21.3 percent of adults aged 18 to 39, about 20.4 million people, had stage 1 or 2 hypertension, yet only 28.3 percent of them knew it. The clinical side, from what the readings mean to treatment, is covered in our complete guide to hypertension.

Special Cases: Pulmonary, Pregnancy and Resistant

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

• Pulmonary hypertension is coded in category I27, not with systemic hypertension. Primary pulmonary hypertension is I27.0, and the I27.2- subcategory covers secondary types.
• Hypertension in pregnancy, childbirth and the puerperium uses O10 to O16: pre-existing hypertension (O10, so chronic hypertension in a pregnant patient is O10, not I10 alone), pre-existing hypertension with pre-eclampsia (O11), gestational hypertension (O13), pre-eclampsia (O14), eclampsia (O15) and unspecified maternal hypertension (O16).
• Resistant hypertension has its own code, I1A.0, added in FY2023. Assign it in addition to the underlying hypertension code, such as I10 or I12.9.

Common Coding Mistakes to Avoid

• Coding “malignant” or “uncontrolled” hypertension separately. There are no such codes. Use I10, or I16.1 if it is a documented hypertensive emergency.
• Coding I10 plus a separate CKD code. When hypertension and CKD coexist, use I12 or I13 with the N18 stage code.
• Forgetting the second code. I11.0, I12, and I13 need the I50 heart failure code and the N18 stage code.
• Using the old stage 3 code. Stage 3 CKD now needs N18.30, N18.31 or N18.32.
• Linking diabetes and hypertension without documentation. Unlike diabetes and CKD, they are not presumed to be related.
• Coding I10 from one high reading. Without a diagnosis, use R03.0.
• Placing pulmonary hypertension in I10. It belongs in category I27.

These details matter beyond the claim. Researchers and health systems use coded data to count and track hypertension, and the codes miss a lot: in a Canadian study of 3,362 patient charts, the best administrative definition picked up 75 percent of people with diagnosed hypertension, and a later systematic review put the figure at about 71 percent. Accurate, specific coding improves those numbers.

Key Takeaways

• The ICD-10 code for hypertension is I10, essential (primary), including stage 1, stage 2, controlled and uncontrolled.
• Heart failure or the listed heart conditions use I11, CKD uses I12, and both use I13, each with the I50 and N18 codes.
• CKD stages 1 to 4 go with I12.9; stage 5 and ESRD go with I12.0.
• Diabetes and CKD are presumed linked (E11.22); diabetes and hypertension are not.
• Secondary hypertension is I15, a crisis is I16, resistant hypertension adds I1A.0, and an elevated reading without a diagnosis is R03.0.

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 heart failure or CKD is documented, add the I50 and N18 codes, keep diabetes and hypertension separate unless the provider links them, use I16 for a crisis, and use R03.0 when there is a high reading but no diagnosis. Codes change each October with the new fiscal year, so check the current ICD-10-CM tabular list and Official Guidelines for anything unusual.