Abstract: Objective To study the clinical diagnostic value of expression levels of β2-microglobulin(β2M), platelet membrane glycoproteins CD62P and CD63 in primary immune thrombocytopenia(ITP). 
Methods In total, 45 patients with ITP who were treated in our hospital were selected as ITP group, 40 patients with moderate or severe anemia as anemia group and 40 healthy people undergoing physical examination during the same period as the control group. The baseline data of the three groups were compared, and platelet(PLT), the mean platelet volume(MPV), plateletcrit(PCT) and platelet distribution width(PDW) of the three groups were detected. The expression levels of β2M, CD62P and CD63 were detected by enzyme-linked immunosorbent assay and compared. The influencing factors of ITP were analyzed, and the diagnostic value of expression levels of β2M, CD62P and CD63 in ITP was analyzed by ROC curve. 
Results There were statistical differences among the control group, anemia group and ITP group with respect to vital signs, PLT, MPV, PCT, and PDW(P＜0.05), among which the ITP group had the lowest level of vital signs, PLT, MPV, PCT, and PDW, followed by anemia group and the control group(P＜0.05). The serum expression levels of β2M, CD62P and CD63 was the lowest in control group, followed by anemia group and ITP group(P＜0.05). Logistic regression analysis showed that the elevated levels of serum β2M, CD62P and CD63 were the influencing factors of primary ITP. Receiver operating characteristic(ROC) curve analysis showed that the combined detection had a higher diagnostic value for ITP than the detection of β2M, CD62P and CD63 alone(P＜0.05). 
Conclusion β2M, CD62P and CD63 are involved in the occurrence and development of ITP. The specificity and sensitivity of combined detection of the three are relatively higher in the early diagnosis of ITP.

Key words: purpura, thrombocytopenic, idiopathic, β2-microglobulin, platelet α granular membrane glycoprotein 140