The JNC 7 Blood Pressure Classification System
| Classification of Blood Pressure for Adults (>18 years of age) |
| Blood Pressure Classification |
Systolic Blood Pressure
(mm Hg) |
Diastolic Blood Pressure
(mm Hg) |
| Normal |
<120 |
and <80 |
| Prehypertension (Normal) |
120–139 |
or 80–89 |
| Stage 1 Hypertension |
140–159 |
or 90–99 |
| Stage 2 Hypertension |
>160 |
or >100 |
FYI | Why use the JNC 7 Classification System?
“Because of the data on lifetime risk of hypertension and the impressive increase in the risk of cardiovascular complications associated with levels of BP previously considered to be normal, the JNC 7 report has introduced a new classification that includes the term “prehypertension” for those with BPs ranging from 120–139 mmHg systolic and/or 80–89 mmHg diastolic. This designation is intended to identify those individuals in whom early intervention by adoption of healthy lifestyles could reduce BP, decrease the rate of progression of BP to hypertensive levels with age, or prevent hypertension entirely.” (JNC 7 Report, 2003) The JNC 8 did not address diagnosis and classification of hypertension.
Classifying your patient’s hypertension
Question 3:
You have brought back your patient, Mary Johnson, for a second appointment to evaluate her blood pressure. From her first visit, she had a blood pressure of 145/80 in both arms taken 2 minutes apart. The rest of her physical exam was negative. Today, you repeat the blood pressures and get 148/ 79 in the left arm and 148/80 in the right arm. How do you diagnose and classify Mary Johnson’s blood pressures? (Choose the best answer)
The correct answer is 3. Mary Johnson has four blood pressure measurements. Two measurements were on the first visit – one on each arm – and both 145/80. She has two more elevated measurements – one on each arm at the second visit: 148/ 79 in the left arm and 148/80 in the right arm. Mary can properly be diagnosed with hypertension. Although her diastolic pressures are in the normal range, her systolic blood pressures are in the Stage 1 range. Therefore you classify her by the worst of the two measurements. She is a patient with Stage 1 essential hypertension.
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Question 4:
What is prehypertension? (Choose the best answer)
The correct answer is 5. – All of the statements are true. “Because of new data on lifetime risk of hypertension and the impressive increase in the risk of cardiovascular complications associated with levels of BP previously considered to be normal, the JNC 7 report has introduced a new classification that includes the term ‘prehypertension’ “ (JNC 7 Report, 2003). The diagnosis of prehypertension is confirmed when an average of two or more blood pressure measurements on separate visits, or equivalent home blood pressures, reveal a DBP of 80-89 mm Hg or SBP of 120-139 mm Hg. These BP ranges are still considered normal and prehypertension is not a disease category. Prehypertension is a designation chosen to identify individuals at high risk of developing hypertension (50% of prehypertensive patients will eventually develop hypertension). Individuals who are prehypertensive are not candidates for drug therapy based on their level of BP and should be strongly encouraged to practice lifestyle modification in order to reduce their risk of developing future hypertension. It is important to recognize that although there is a known correlation between blood pressure level and mortality, it has not been shown systematically in trials that treating patients with prehypertension improves outcomes.
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