The antibody was tested by western blot on samples from human embryonic stem cells but did not detect the expected signal at the predicted size of around 100 kDa in either the stem cells or the positive control. The western blot procedure involved extracting protein from stem cell pellets and supernatant using RIPA buffer, running samples on an 8% SDS-PAGE gel and transferring to a membrane. The membrane was blocked for 1 hour before an overnight incubation with the primary antibody at a 1:500 dilution, followed by washing and a 1 hour incubation with a secondary antibody at a 1:10,000 dilution before detection. No band was observed at the expected molecular weight of around 100 kDa.