The WHO ICD-11 classification is very different from the 10th version that the United States modified to create the ICD-10-CM code set that is used for morbidity reporting in the US today. That includes hypertension ICD codes.
Here are codes for a common condition to compare and contrast. Code assignments reflect the closest equivalent code from each code set as of the present date. Code category comparisons reflect excerpts from the ICD-11 Browser compared to the ICD-10-CM Tabular listing.
| WHO ICD-11 | United States ICD-10-CM |
| Code Assignment for Unspecified Hypertension | |
| BA00.Z Essential hypertension, unspecified | I10 Essential (primary) hypertension |
| Comparison of Code Categories | |
| BA00 Essential hypertension BA00.0 Combined diastolic and systolic hypertension BA00.1 Isolated diastolic hypertension BA00.2 Isolated systolic hypertension BA00.Y Other specified essential hypertension BA00.Z Essential hypertension, unspecified Matching terms: hypertension NOS, essential hypertension, idiopathic hypertension, primary hypertension, arterial hypertension NOS | I10 Essential (primary) hypertension Includes: High blood pressure Hypertension (arterial) (benign) (essential) (malignant) (primary) (systemic) |
As illustrated in the comparisons in the table above, ICD-11 codes have a different structure than prior versions. There are four alphanumeric characters to the left of the decimal point, instead of three characters. In ICD-11, hypertension is classified within Chapter 11 (Diseases of the circulatory system) where the codes begin with BA–. In ICD-10-CM, hypertension is classified in Chapter 9 (also focused on Diseases of the circulatory system) where the codes start with the letter ‘I’.
Go to the WHO website to browse ICD-11 codes or use the ICD-11 coding tool. It’s fun to browse the ICD-11 hierarchy and look at some of the codes for conditions you code frequently with ICD-10-CM in the US today.
About Mary H. Stanfill
Mary H. Stanfill is Vice President of Consulting for UASI – United Audit Systems, Inc. and is the official representative of the IFHIMA to the WHO Family of International Classifications Education and Implementation (EIC) and Morbidity Reference Group (MbRG) workgroups. She has over 35 years of experience in the health information profession, primarily focused on clinical classification of healthcare data. She holds a master’s in biomedical informatics and is currently pursuing a doctorate in health informatics. Check our blog every month for more code comparisons from Stanfill.
