A representative image of a gelatin zymogram used for MMP scoring in a MMP test. The lanes represent uterine fluid samples from individual patients with recurrent implantation failure (RIF). Lanes 1, 2, 3, 4 and 6 were scored 4, 2, 4, 8 and 0, respectively. Lane 5 shows a result from the standard used in the present study (supernatant of BHK9 breast carcinoma cell culture). Details of the scoring system are described in the Methods section.