There are several blood tests doctors use to diagnose heart failure. Most patients have labs drawn at scheduled times. You may have labs drawn more often if your team feels that you need closer surveillance. 

BNP (Brain Natriuretic Peptide)
BNP is a hormone that is released from your heart and blood vessels when they are working harder for long periods of time. When there is more BNP in the bloodstream, this can indicate that the heart is overworked or stretched.

Renal Panel
A renal panel checks how well the kidneys are working. If they have reduced blood flow because of heart failure, the levels may be elevated.

Liver Function Test
A liver function test checks how well the liver is working. If the liver is congested or has too much blood backing up from the heart, the levels may be elevated.