Answer: "Uncontrolled" does not equal "malignant." To use a malignant hypertension diagnosis, your cardiologist has to specifically say that in his documentation. The word "uncontrolled" does not affect code assignment. The type of hypertension is what drives your hypertension code selection. You should use 401.9 (Essential hypertension; unspecified) instead.
Unfortunately, physicians will use words that mean one thing in ICD-9 but something else to them. When your cardiologist is vague about the type of hypertension, you should ask the physician what he means, have him clarify it in the medical record, and then assign the ICD-9 code accordingly. Keep in mind: Hypertension, commonly referred to as "high blood pressure" or "HTN," is a medical condition in which the blood pressure is chronically elevated. Malignant hypertension is a complication of hypertension characterized by very elevated blood pressure, and organ damage in the eyes, brain, lung and/or kidneys. -- You Be the Coder and Reader Questions were prepared with the assistance of Jim Collins, ACS-CA, CHCC, CPC, CEO of the Cardiology Coalition and compliance manager for several cardiology groups around the country; and reviewed by Jerome Williams Jr., MD, FACC, a cardiologist with Mid Carolina Cardiology in Charlotte, N.C.