荧光原位杂交检测BcR／ABL融合基因假阳性结果的校正

Calibration of false positive result in detection of BCR/ABL using fluorescence in situ hybridization

目的探讨荧光原位杂交（fluorescenceinsituhybridization，FISH）检测BCR／ABL融合基因时假阳性信号对结果的影响，并探讨校正结果的方法。方法将阴性标本与BCR／ABL双色双融合（dual—colordualfusion，DCDF）、探针信号表现为1红2绿1融合（1R2G1F）且额外信号（extrasignal，ES）探针信号表现为1红1绿1融合（1R1G1F）的阳性标本按不同比例混合，分别应用BCR／ABLDCDF探针及ES探针对不同比例混合的标本进行检测，并对不同的混合比例下DF探针检测的结果以及ES探针校正前后的结果与理论值使用二项分布进行对比。结果随着阴性细胞比例的增高，假阳性率增加。阴性、5％、10％及25％阳性水平，未经校正ES探针的计数结果与理论值差异有统计学意义（P〈0．05）；50％及90％阳性水平，未经校正ES探针的计数结果与理论值差异无统计学意义（P〉0．05）。校正后ES探针的计数结果与理论值差异无统计学意义（P〉0．05）。结论对荧光原位杂交信号表现为1R1G1F的结果进行校正，能在一定程度上消除信号叠加所造成的假阳性，从而为低阳性水平标本提供更为可靠的结果。

Objective To explore the effect of false positive signals during detection of BCR/ABL fusion gene by fluorescence in situ hybridization （FISH）, and develop a method for calibration. Methods Normal specimens were mixed with BCR/ABL positive specimens in which presented signal pattern of 1-red- 2-green-l-fusion （1R2G1F） using dual color dual fusion （DCDF） probes and 1-red-l-green-l-fusion （1R1GIF） using extra signal （ES） probes in different proportions. Mixed samples were detected using DCDF and ES probes. Results of DCDF probes, ES probe before calibration, ES probes after calibration and theoretical results were compared by binomial distribution in different proportions. Results The rate of false positive signals has risen with increase of negative rate. A significant difference was found between theoretical proportion and results without calibration in negative level, 5%, 10% and 25% positive level （ P〈0.05）. There was no significant difference between theoretical proportion and results without calibration in 50% and 90% positive level （P〉0.05）. Also there was no significant difference between theoretical proportion and calibrated results （P〉 0. 05）. Conclusion Calibration of FISH result can delimitate the effect of false positives, and can provide more reliable results in cases with low level positive rates.