What are the advantages of avidin-biotin complex (ABC) method?

One advantage is that avidin exhibits a strong attraction to biotin. Due to this, the bond formed between them is nearly irreversible. Another advantage is that more enzyme reporter is found at the site of the target antigen, leading to the amplification of a more intense signal. This also leads to increased detection efficiency. Using the ABC method typically requires less primary antibody compared to direct detection methods. This is because the secondary antibody in the ABC method is conjugated to biotin. Additionally, compared to the peroxidase anti-peroxidase (PAP) method, the ABC method often offers reduced assay time.