XDx is a nov­el mol­e­c­u­lar diag­nos­tics com­pa­ny whose mis­sion is to improve patient care by devel­op­ing mol­e­c­u­lar diag­nos­tics that trans­late an individual’s immune sta­tus into clin­i­cal­ly action­able infor­ma­tion. The Com­pa­ny has devel­oped an accu­rate blood-based diag­nos­tic test to detect rejec­tion in heart trans­plant patients. The test mea­sures the lev­el of gene expres­sion for the set of genes most close­ly involved in the immune response of heart trans­plant tis­sue rejec­tion. The test will par­tial­ly replace biop­sies, which are more cost­ly, painful, invasive/​risky, sub­jec­tive, non-quan­ti­ta­tive and slow­er to detect organ rejec­tion. XDx is devel­op­ing sim­i­lar tests for oth­er organ trans­plants such as lung trans­plants, as well as tests for autoim­mune dis­or­ders. In addi­tion to DBL Part­ners, investors include Klein­er Perkins Cau­field and Byers, Texas Pacif­ic Group, New Leaf Ven­ture Part­ners, Bur­rill and Com­pa­ny, Inte­gral Cap­i­tal Part­ners, Intel Cap­i­tal Part­ners and Duff Ack­er­man and Goodrich.