Anesthesia Coding Alert

Diagnosis Focus:

Get Your Hypertension Coding Under Control: Part 1

Published on Wed Feb 07, 2024

Remember: A high blood pressure reading doesn’t always mean hypertension.

With 12 different types, primary and secondary diagnoses, and instructions for sequencing and adding additional codes, there’s a lot to remember when you code hypertension (HTN).

So, whether you’re new to coding or you just need a timely refresher, you’ll find what you need to keep everything straight when you read through the insights and pointers in our two-part series. Here are six steps you can take to keep your HTN coding on the up and up.

Review the Most Recent Hypertension Guidelines

High blood pressure develops when blood flows through the arteries at higher-than-normal pressures. Blood pressure is recorded as two numbers:

Systolic blood pressure (the first number) indicates how much pressure the blood is exerting against artery walls when the heart contracts.
Diastolic blood pressure (the second number) indicates how much pressure blood is exerting against artery walls while the heart muscle is resting between contractions.

“Elevated blood pressure is when readings consistently range from 120-129 systolic and less than 80 mm Hg diastolic ... Hypertension Stage 1 is when blood pressure consistently ranges from 130 to 139 systolic or 80 to 89 mm Hg diastolic … Hypertension Stage 2 is when blood pressure consistently is 140/90 mm Hg or higher,” according to the American Heart Association.

High blood pressure is considered severe when blood pressure exceeds 180/120, says Carol Hodge, CPC, CPMA, CDEO, CCC, CEMC, CPB, CFPC, COBGC, senior documentation specialist at St. Joseph’s/Candler Medical Group. This stage is known as a hypertensive crisis and may require medical attention if readings remain high or are associated with symptoms indicative of organ damage such as chest pain or shortness of breath.

Pause Before Coding High Blood Pressure as HTN

It’s important to note that one high blood pressure reading does not mean the patient has HTN. At least two elevated readings (taken on separate occasions) are usually required to establish a diagnosis of hypertension.

If the documentation indicates an episode of elevated blood pressure in a patient who has not been given a formal diagnosis of HTN or high blood pressure as an isolated incidental finding, report R03.0 (Elevated blood-pressure reading, without diagnosis of hypertension). Assign code R03.0 unless the patient has an established diagnosis of hypertension, per the ICD-10-CM guidelines.

Caution: If the patient has transient hypertension of pregnancy, look to O13.- (Gestational (pregnancy-induced) hypertension without significant proteinuria) or O14.- (Pre-eclampsia) instead of R03.0.

Understand How To Handle Controlled, Uncontrolled HTN

If the provider documents controlled HTN, this diagnostic statement typically refers to an existing state of hypertension under control by therapy, whereas uncontrolled HTN denotes untreated hypertension or that the patient’s blood pressure is not responding to their current HTN treatment regimen. In either case, you should report the appropriate code from categories I10-(Essential (primary) hypertension) through I15.- (Secondary hypertension), per the guidelines.

Dial Into These 3 Codes for Hypertensive Crisis

The last stage of high blood pressure is known as hypertensive crisis, which is diagnosed when there is a severe rapid increase in blood pressure, typically with readings that exceed 180/120 mm Hg. Hypertensive crisis is divided into two categories: urgent, which means the patient has extremely high blood pressure but with no suspected organ damage, and emergent, which indicates extremely high blood pressure that has caused damage to a patient’s organs.

Report one of the following codes from category I16.- (Hypertensive crisis) based on the physician’s documentation:

I16.0 (Hypertensive urgency)
I16.1 (Hypertensive emergency)
I16.9 (Hypertensive crisis, unspecified)

Coding tip: When reporting a code from category I16.-, also report any identified hypertensive disease (I10-I15.-, I1A.- (Other hypertension). Sequence these codes based on the reason for the encounter.

Recognize Secondary HTN Is Due to an Underlying Condition

Secondary hypertension is high blood pressure caused by another medical condition, such as those that affect the kidneys, arteries, heart, or endocrine system, says Rebecca Sanzone, CPC, CPMA, quality assurance specialist at St. Vincent Medical Group/Ascension Health and coding consultant at the American College of Cardiology. Secondary HTN can also develop during pregnancy.

When your provider documents secondary hypertension, report two codes on your claim: one code to identify the underlying etiology and another from category I15.- to denote the specific type of hypertension. Sequencing of codes is determined by the reason for the encounter.

Pay Attention to Resistant HTN Coding Particulars

Report I1A.0 (Resistant hypertension) when resistant hypertension is documented or the provider notes “apparent treatment resistant hypertension,” “treatment resistant hypertension,” or “true resistant hypertension.”

Code first: You will see a note with I1A.0 instructing you to code first the specific type of existing hypertension, if known, such as essential or secondary hypertension.

Don’t miss: Per the guidelines, resistant hypertension refers to the blood pressure of a patient with hypertension that remains above goal despite the use of antihypertensive medications.

Stay tuned: We’ll delve into more hypertension coding key concepts next month.