The present invention is directed to an isolated peptide that functionally mimics a binding site for a monoclonal antibody, the monoclonal antibody recognizing an epitope within the human platelet glycoprotein Ib/IX complex. This peptide is called a mimotope. The invention also provides an isolated molecule capable of binding to the peptide, or the mimotope, which molecule can be an antibody, a second peptide, a carbohydrate, a DNA molecule, an RNA molecule, or other naturally or chemically synthesized molecules. This isolated molecule is called an anti-mimotope. Mimotopes mimicking the binding site for monoclonal antibody C-34 and SZ-2, as well as anti-mimotopes to the C-34 mimotopes, are specifically provided.