Compositions for use in diagnostic screens for Mycoplasma haemofelis are provided. In one embodiment an immunogenic peptide selected from SEQ ID NO: 1 to SEQ ID NO: 60, or a fragment thereof, is immobilized on a solid support and is used to detect the presence of Mycoplasma haemofelis antibodies in a patient bodily fluid. In accordance with one embodiment a method for detecting a Mycoplasma haemofelis infection in a feline species, is provided.