Single-tube bi-directional allele specific amplification (SB-ASA) and real-time quantitative polymerase chain reaction (RQ-PCR) assays were developed and performed for JAK2V617F detection on 40 polycythemia vera (PV) samples,31 essential thrombocythemia (ET) samples,40 acute leukemia samples,and 40 healthy control samples.Differences between detect limitations of the two assays and their influence on the mutation detection rate were analyzed.The results showed that in some samples,the JAK2V617F burden was as low as nearly 1%,and thus more JAK2V617F-positive samples were detected by RQ-PCR than by SB-ASA assay due to the former higher detect limitation.Mutation allele ratios in PV and ET samples and their relevance to biological characteristics were also analyzed.The results showed that the mutation allele ratio was 0.436±0.261 in PV,higher than the 0.216±0.207 in ET;percentage of certainly homozygous mutation carriers in PV was 40.54%,higher than the 10% in ET.However,statistical analysis showed no relevance between mutation allele burden and sex or age.Our result shows that the pathogenesis of PV and ET may be related to the mutation allele burden of JAK2V617F.