Free CD33 concentration in plasmaand leukocyte count, the number of blast cells in blood of 21 patients with (AML) is determined at the time points: pre-treatment (N1T0) and every three day after treatment (N1Tl, N1T2, N1T3, N1T4, N1TS, N1T6 and N1T7). Free CD33 concentration in plasma Is determined by Phage Display Real time Immuno - PCR (PDRTI-PCR) using antigen CD33 products and phase sc-Fv recombinant antibody from human. 28 normal people In control group have CD33td1plasma 12,6:!: 7,1 ng/mL and cut-off Is 22,9 ng/mL The results indicated that In the first chemotherapy treatment, the average of leukocyte count, the number of blast cells In blood is highest before treatment phase 1 (N1T0) and) and then decreased gradually in the time period. Concentration of free CD33 In plasma of AML patients in all point is highger than normal person. The average concentration of free CD33 in plasma is highest in 9th day and then decreased gradually in the time period of the first chemotherapy.