BNP Blood Test in California

What this test measures

BNP is released by the heart muscle when the ventricles are stretched, as can happen when the heart does not pump efficiently. The hormone helps the body regulate fluid and blood pressure by promoting sodium and water excretion. Because it rises with cardiac wall stress, measuring it in blood gives clinicians a biochemical clue about how the heart is handling its workload.

The test uses a blood sample, usually drawn from a vein in the arm. Laboratories may measure BNP directly or measure NT-proBNP, an inactive fragment produced alongside it. Both are used clinically, and reference ranges differ between the two assays. Results are interpreted with the person's symptoms, examination, and imaging rather than on their own, since many factors influence the level.

BNP testing is commonly ordered when someone arrives with shortness of breath and the cause is unclear, because it can help distinguish a cardiac cause from a lung-related one. It is also used to gauge severity and to monitor people with known heart failure. Levels can be affected by age, kidney function, and other conditions, so the result always belongs in a broader clinical picture.