Two-stage screening strategies Whilespecificityforanybloodbiomarkercanbeset at98%,thesensitivityforearlystagepre-diagnostic disease remains a vital concern. To improve the sensitivity of an existing marker while maintaining the high specificity, retrospective analyses of CA125 data from ovarian cancer screening trials conductedinthe1980sand1990swereundertaken. These analyses demonstrated that CA125 profiles over time differentiated subjects diagnosed with ovarian cancer from all other subjects. In ovarian cancer cases, CA125 increased exponentially over timewhile,inmostothersubjects,CA125wasrelativelystable.