Indirect ELISA analysis of M13 was performed by coating HSA/BSA (2 μg/mL in pH 9.6 carbonate buffer) in 96-well plate, and then add the indicated amounts of M13 Bacteriophages displaying anti-HSA Fab overnight at 4℃. Incubated with 100 µl per well of anti-M13 monoclonal antibody starting at a dilution of 1/2,500 and serially diluting it to a dilution of 1:160,000 for 1 hours at room temperature. The plate was washed and incubated with 50 µl per well of an HRP-conjugated goat anti-Mouse IgG secondary antibody (HA1006) at a dilution of 1:10,000 for one hour at room temperature. Detection was performed using an Ultra TMB Substrate for 10 minutes at room temperature in the dark. The reaction was stopped with sulfuric acid and absorbances were read on a spectrophotometer at 450 nm.