Disclosed is a method of detecting human MMP9 in a sample, comprising: a) contacting the sample with an antibody or antigen-binding fragment thereof comprising a heavy chain variable (VH) region and a light chain variable (VL), wherein the heavy chain variable region comprises a CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 34, a CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 35, and a CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 36； wherein the light chain variable domain (VL) comprises a CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 37, a CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 38, and a CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 39； and b) detecting binding of the antibody or antigen-binding fragment thereof to human MMP9 in the sample, thereby detecting the presence or absence of the human MMP9.
