【Abstract】 To explore the application of platelet alarm information of Sysmex XE2100 electric resistance method (PLTI), optics (PLT), Sysmex XN3000 nucleic acid staining method (PLTF) and cella vision DM96 at low values of platelet count. Methods182 patients with platelet count <100 * 109/L measure by XE2100 automatic blood cell analyzer (impedance method) (PLTI) were selected. The specimens from the patients were detected with XE2100 automatic blood cell analyzer (optical method) (PLTO), XN3000 blood cell analyzer (staining method) (PLTF), DM96 automatic blood cell morphology analyzer and Sysmex sp1000i automatic push piece dyeing instrument (DM96). The alarm information was divided into abnormal platelet histogram (Plt Abn Dst), thrombocytopenia (Thrombocytopenia) and platelet aggregation (Plt Clumps). The correlation of PLTI, PLTO, PLTF and DM96 was analyzed. Results The abnormal imformation of platelet histogram and platelet aggregation of PLTO and PLTI was not different (P>005). There were differences abnormal imformation of platelet histogram and platelet aggregation between PLTO and PLTF, between PLTI and PLTF, between PLTOand DM96 and between PLTI and DM96 (P<005). There were no diferences of thrombocytopenia between PLTO and PLTI, between PLTO and PLTF and between PLTI and PLTF (P>005). There were diferences of thrombocytopenia between PLTO and DM96，between PLTF and DM96 and between PLTIand DM96 (P<005). Conclusion In the low value of platelet (<100* 109/L) count, the different warning information should choose different counting methods. In the instrument tip PLT Abn DST and PLT Clumps alarm information, the reticulocyte red channel optical method of platelet count cannot be corrected platelet count must be by nucleic acid staining method (PLTF) or DM96 platelet count, and the instrument tip thrombocytopenia alarm information must use DM96 in order to pass the inspection of the platelet count issued a report.