BNP, as an active protein hormone, has a short biological half-life of 20 minutes. NT-ProBNP, inactive fragment, has a half-life of 1-2 hours. Both are increased in CHF and both levels correlate to the severity of condition. In the future these two hormones may be used as prognostic indicators in ACS also; studies have shown that levels predict cardiac mortality and adverse cardiac events in patients with ACS.
Because of its longer half-life, there are advantages to measuring NT-ProBNP over BNP. In CHF patients receiving exogenous and synthetic BNP for treatment, BNP levels may be affected while NT-ProBNP will not be affected. NT-ProBNP is thought to be primarily cleared by kidneys and therefore falsely elevated in severe renal disease.