The present invention relates to an antibody that specifically binds a mutated NT-proBNP comprising i) a mutation substituting arginine at position 46 with histidine or ii) a mutation substituting glutamic acid at position 43 with aspartic acid. Moreover, the present invention relates to a mutated NT-proBNP or fragment thereof. Further, envisaged by the present invention are kits comprising the antibody of the present invention, or the mutated NT-proBNP of the present invention. The present invention also concerns a method for diagnosing heart failure.
