by Wyn Staheli, Director of Content - innoviHealth
and Aimee L. Wilcox, CPMA, CCS-P, CST, MA, MT
Apr 16th, 2020
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.
Note: If there is acute renal failure, add that code. |
| w/ chronic kidney disease | Patient has CKD classifiable with N18-
|
| 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
|
| 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 | |
| w/ pulmonary involvement | |
| 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- |
| 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 |
About Wyn Staheli, Director of Content - innoviHealth
Wyn Staheli is the Director of Content Research for innovHealth. She has over 30 years of experience in the healthcare industry. With her degree in Management Information Systems (MIS), she has been a programmer for a large insurance carrier as well as a California hospital system. She is also the author and editor of many medical resource books and the founder of InstaCode Institute.
About Aimee L. Wilcox, CPMA, CCS-P, CST, MA, MT
Aimee L. Wilcox is a medical coding, billing, and auditing consultant, author, and educator with more than 30 years of clinical and administrative experience in healthcare, coding, billing, and auditing. Medicine, including coding and billing, is a constantly changing field full of challenges and learning and she loves both. Aimee believes there are talented medical professionals who, with proper training and excellent information, can continue to practice the art of healing while feeling secure in their billing and reimbursement for such care.
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