thrombocytopenia A laboratory test result indicating that there is an abnormally small number of platelets in the circulating blood. DOID:1588 ICD10:D69.6 ICD9:287.5 MESH:D013921 MONDO:0002049 NCIT:C3408 OMIMPS:313900 SCTID:302215000 UMLS:C0040034 UMLS:CN130080 platelet count decreased thrombocytopenic disorder blood platelet disease