Are blood tests useful in monitoring heart failure?

Heart failure and the medications used to treat it can affect your liver and kidney function and the balance of electrolytes in your blood. Blood tests that assess these factors can help your provider monitor your condition and your response to treatment. You may need to regularly repeat certain blood tests throughout your treatment.

Electrolyte tests determine if there are imbalances of minerals in the blood—such as sodium and potassium—that can accompany heart failure and heart failure treatment.

The following drug classes may affect or interact with blood electrolyte levels:

  • angiotensin-converting–enzyme (ACE) inhibitors
  • angiotensin-receptor blockers (ARBs)
  • angiotensin receptor–neprilysin inhibitor (ARNI)
  • aldosterone receptor antagonists
  • diuretics
  • digoxin.

Liver and kidney function tests look for chemicals in the blood that signal abnormalities in the liver or kidneys.

The following drug classes may affect liver and kidney function:

  • angiotensin-converting–enzyme (ACE) inhibitors
  • angiotensin-receptor blockers (ARBs)
  • angiotensin receptor–neprilysin inhibitor (ARNI)
  • aldosterone receptor antagonists
  • diuretics
  • digoxin.

Brain-type natriuretic peptide (BNP) blood test. When blood backs up into the heart because it isn’t being pumped out efficiently, pressure rises in the ventricles. The heart cells register this change and sharply boost the secretion of a hormone called brain or B-type natriuretic peptide (BNP). Over the last decade, the measurement of a person’s blood level of BNP, facilitated by a rapid bedside test, has become a valuable tool for assessing heart muscle weakness and predicting the likelihood of future heart failure hospitalizations and death. A related substance, N-terminal-pro-B-type natriuretic peptide (NT-pro-BNP), is also used in heart failure diagnosis.

Testing for BNP may be useful for gauging effectiveness of heart failure treatment as well as for diagnosis. Blood levels of the hormone correlate with the severity of heart failure symptoms. In addition, levels appear to drop when people undergo aggressive medical treatment for heart failure. But so far, clinical trials examining the use of repeated Natriuretic peptide measurements to guide drug therapy haven’t shown that this approach improves survival.