In my clinical rotation, I see different lab values and results every day. Most people probably don’t realize how many lab values Registered Dietitians come across on a daily basis in the clinical world. Most of these I was already very familiar with, such as glucose, triglycerides, cholesterol, sodium, chloride, potassium, and albumin. But today I came across “BNP” and thought I’d share what I learned.
BNP stands for B-type-Natriuretic Peptide and is secreted by the ventricles (lower chambers in the heart) in response to pressure changes in the heart. BNP is a predictor of the severity of congestive heart failure, or CHF. So when heart failure worsens, the level of BNP in the blood increases. When heart failure is stable, BNP decreases in the blood. However, those with stable heart failure still have higher BNP levels than those patients with no heart failure.
Levels of BNP in the blood indicate different degrees of severity of the heart failure:
- BNP levels below 100 pg/mL indicate no heart failure
- BNP levels of 100-300 suggest heart failure is present
- BNP levels above 300 pg/mL indicate mild heart failure
- BNP levels above 600 pg/mL indicate moderate heart failure.
- BNP levels above 900 pg/mL indicate severe heart failure.
The patient I saw today had a BNP of slightly over 300 pg/mL, which indicates mild heart failure. I spoke to a dietitian today who said she has seen patients with a BNP level of over 9000 pg/mL (yes, over nine thousand!), indicating severe heart failure.
A study has shown that the BNP blood test accurately predicts CHF 81.1% of the time, while physician’s judgement alone (without looking at BNP levels) is accurate 74% of the time. While BNP testing isn’t a substitute for years of a physician’s medical experience and knowledge, it is still a helpful diagnostic tool that is also quick and inexpensive.
Krause’s Food & Nutrition Therapy, 12th Ed., L. Kathleen Mahan & Sylvia Escott-Stump