FAP and colorectal carcinoma: Werner S et al tested serum samples from 1660 blood samples from participants in a colonoscopy screening with a 5-marker blood test (CEA, anti-p53, osteopontin, seprase and ferritin) and found that the diagnostic performance for CRC of the 5-marker test was comparable with that of the guaiac-based fecal occult blood test (gFOBT), as they both identify 39% of all CRC cases at the specificity of 96% [22].