GICA or CA 19-9, monosialyl Lewis (a) antigen, is a ganglioside, component of cellular wall. GICA is known as a neoplastic marker with high correlation, specificity and sensibility for the gastrointestinal neoplasms, mainly of the pancreas. Two cases of intravascular haemolysis are reported (a case in woman with Moschowitz's syndrome and a case in man with mitral prosthetic valve and mild congestive heart failure) with elevated serum levels of GICA. First in the literature, the Authors hypothesize a strict correlation between the aspecific elevation of GICA serum levels and diffuse membrane cell damage in several body districts, and its significance (1-6%) in hemolytic, non neoplastic pathology. Its serum evaluation will be useful in the early diagnosis and follow-up of hemolytic pictures associated with several diseases (e.g.: thrombotic microangiopathies, as TTP, HUS, HELLP, etc; hemolysis by prosthetic valves, congenital cardiopathies, etc.; liver diseases; hemolytic anemias caused by intra- and extra-corpuscular defects). The literature is widely reviewed about significance of GICA serum elevation in neoplastic pathology, its diagnostic pitfall even in the presence of neoplastic diseases, aspecific elevation in non neoplastic diseases and its correlation with other illnesses.