Terminal pro-brain natriuretic peptide (NT-proBNP) is a prohormone with a 76 amino acid N-terminal inactive protein that is cleaved from the molecule to release brain natriuretic peptide (BNP)1. NT-proBNP may affect cardio-renal homeostasis and it can oduction of cGMP although its potency is very low compared to brain natriuretic peptide 32. C Reactive Protein (CRP) can interact with NT-proBNP, thus a functional binding ELISA assay was conducted to detect the interaction of recombinant human NT-proBNP and recombinant human CRP. Briefly, NT-proBNP was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to CRP-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-NT-proBNP pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody for 1h at 37℃, wells were aspirated and washed 5 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37℃. Finally, add 50 µL stop solution to the wells and read at 450/630 nm immediately. The binding activity of recombinant human NT-proBNP and recombinant human CRP was shown in Figure 1, the EC50 for this effect is 4.2 ug/mL.