Hypertension ICD-10-CM Coding Table, Guidelines, and Tips

April 16th, 2020 - Wyn Staheli, Director of Research & Aimee Wilcox, Director of Content

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Hypertension Definitions

Blood pressure is the measurement of blood pressing on the blood vessel walls when the heart contracts, pushing blood through the arteries (systolic pressure) and when the heart is at rest between heart contractions when it is refilling with oxygenated blood (diastolic pressure). A patient may be considered hypertensive if either of the systolic or diastolic pressure is elevated while the other is normal or both are elevated.

Blood pressure is measured using a sphygmomanometer (blood pressure cuff with an attached gauge) and a stethoscope. Blood pressure is measured in millimeters of mercury (mmHg) and documented as systolic over diastolic (e.g., 120/80 mmHg). Both systolic and diastolic pressures can indicate hypertension independently or together. The following table identifies five types of systolic and diastolic blood pressure readings and what they indicate.

Type Systolic Diastolic
Normal Less than 120 Less than 80
Elevated 120-129 Less than 80
Hypertension (stage 1) 130-139 80-89
Hypertension (stage 2) 140 179 90-119
Hypertensive crisis 180 or higher 120 or higher

There are many factors that can contribute to or cause high blood pressure and hypertension (e.g., tobacco use or exposure, obesity, stress, pregnancy) and several ICD-10-CM code categories to report them. Documentation is important for code selection in identifying these additional factors.

Other Hypertension Definitions

Essential hypertension, also known as arterial, benign, idiopathic, primary, or malignant hypertension, has no known or identified cause and is reported with code I10 as long as there are no associated and/or related causal relationships (e.g, heart disease).

Secondary hypertension is caused by an underlying condition or disease (e.g., chronic kidney disease, heart disease) and is reported with either a combination code (e.g., I11.9 hypertensive heart disease without heart failure) OR multiple codes to further explain the underlying condition, stage, or complicating factors as in the following example:

I12.0 Hypertensive chronic kidney disease with stage 5 chronic kidney disease or end stage renal disease, and
N18.5 Chronic kidney disease, stage 5

Hypertension Coding Tips

According to the ICD-10-CM Official Coding Guidelines Section 1;C.9.a, a causal relationship is presumed between hypertension and heart involvement as well as hypertension and kidney involvement, even when the provider has not specifically linked the two conditions together in the documentation (unless they are specifically noted as “unrelated”).

The guidelines also state that “For hypertension and conditions not specifically linked by relational terms such as “with,” “associated with” or “due to” in the classification, provider documentation must link the conditions in order to code them as related.”

An elevated blood pressure reading that is not documented as hypertension is reported as a symptom (R03.0). If the patient is pregnant, use the appropriate pregnancy codes (O13.- or O14.-) instead of code R03.0.
Be sure to review Section 1;C.9.a of the ICD-10-CM Official Guidelines for Coding & Reporting for very specific hypertension reporting guidelines which need to be followed. For those with a Find-A-Code subscription, they may be easily viewed by clicking on the [ICD-10 Official Documentation Guidelines] tab below code I10.

ICD-10-CM Hypertension Coding Table

For those that remember using ICD-9-CM, there was a hypertension table located in the Index (Volume 1) which was divided into categories of malignant, benign, and unspecified hypertension. With ICD-10-CM, those categories no longer exist. The following hypertension table, created by innoviHealth, identifies some of the coding options for reporting high blood pressure, hypertension, and hypertension with causal relationships.

Condition(s)	Coding Guidance
Essential (primary)	I10 if there are no associated causal relationships (e.g., heart disease)
w/ cardiorenal disease	I13-: this combination code includes hypertension, heart disease, and CKD. If there is heart failure, use additional code from category I50- Do not use with codes from categories I11- and I12-. Note: If there is acute renal failure, add that code.
w/ chronic kidney disease	Patient has CKD classifiable with N18- I12-: this combination code includes hypertension and CKD N18- is sequenced first, followed by I12- if there is also kidney involvement, see cardiorenal. Note: If there is acute renal failure, add that code
w/ eye involvement	Report a code from subcategory H35.0- and a code from categories I10-I15. Sequence according to the reason for the encounter.
w/ heart disease	Patient has heart condition classified with I50- or I51.4-I51.9 hypertension is related: use code from category I11- hypertension is unrelated: sequence according to reason for the encounter Note: If there is also kidney involvement, use cardiorenal codes instead.
w/ kidney involvement	Hypertensive renal disease NOS or CKD stages 1-4 use code I12.9. Otherwise,see cardiorenal disease codes. Note: If there is also heart involvement, use cardiorenal codes instead.
w/ pregnancy	pre-existing: see O10- and O11- pregnancy-induced: see O13-, O14-, O16-
w/ pulmonary involvement	pulmonary hypertension: use code from I27- secondary pulmonary hypertension (I27.1, I27.2-), code also any associated conditions or adverse effects of drugs or toxins sequence according to reason for the encounter, except for adverse effects of drugs (See Section I.C.19.e.)
Cerebrovascular disease	When hypertension is due to cerebrovascular disease, code first the applicable code from categories I60-I69, then report applicable hypertension code.
Hypertensive crisis	Blood pressure is 180/120 or greater. Use code from category I16- Code also any identified hypertensive disease (I10-I15) Sequence according to reason for the encounter.
Hypertensive encephalopathy	Brain dysfunction or damage resulting from sustained hypertension. When blood pressure exceeds the limits of cerebral autoregulation, cerebral blood flow is impaired (brain ischemia). Report with code I67.4.
Secondary	Hypertension is due to underlying condition not otherwise classified. Two codes are required: one to identify the underlying etiology and one from category I15- to identify the hypertension. Sequence according to reason for the encounter.
Transient	An elevated blood pressure reading without a diagnosis of hypertension is also referred to as “transient hypertension.” Report with code R03.0

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Type	Systolic	Diastolic
Normal	Less than 120	Less than 80
Elevated	120-129	Less than 80
Hypertension (stage 1)	130-139	80-89
Hypertension (stage 2)	140 179	90-119
Hypertensive crisis	180 or higher	120 or higher