Transmissible spongiform encephalopathy (TSE) is diagnosed in a subject by using mass spectrometry to observe a polypeptide in a sample of body fluid taken from the subject. The polypeptide is differentially contained in the body fluid of TSE-infected subjects and non-infected subjects, and has a molecular weight in the range of from 1000 to 100000, but excluding the rang e of from 3500 to 30000. TSE can be diagnosed in a subject by determining a te st amount of a polypeptide in a sample of body fluid, wherein the polypeptide i s Cystatin C or a haemoglobin, a haemoglobin chain or a truncated chain or a fragment thereof which exhibits an immunological reaction to an antibody to bovine haemoglobin.
DIAGNOSTIC METHOD FOR TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES (PRION DISEASES)