目前, 核酸检测已成为了我国新型冠状病毒感染确诊的“金标准”, 然而核酸检测在检测过程中受到病程、 标本采集、 检测过程、 检测试剂等因素的影响, 容易出现检测结果“假阴性”而漏诊的情况。 检测血清中的新型冠状病毒特异性IgM和IgG抗体已作为新冠病毒检测的辅助手段, 可以用来弥补核酸检测的“假阴性”短板, 提高检测阳性率。 论文介绍了一种成本低的便携式新冠IgM和IgG抗体定量检测仪。 检测仪由CPU信号处理模块、 光源驱动模块、 多光谱探测模块、 电源模块、 显示存储和通信模块等组成。 采用荧光免疫层析技术使待测样本中的IgM和IgG抗体与量子点相结合, 并将其截留在试纸条的T线。 方波调制后的光源驱动模块驱动紫外LED, 其出射紫外光通过一种屋脊形的光学系统垂直照射在免疫荧光层析试纸条的T线和C线上, 量子点标记物被光源激发辐射出红色荧光, 红色荧光透过窄带滤光片后被多光谱探测模块所捕获； 多光谱信号在CPU中进行FFT变换得到其频谱特征量, 利用信号波段和参考波段的特征量的比值进行归一化处理消除背景和环境干扰信号计算得到荧光强度, 根据标定系数, 从而确定IgM和IgG抗体的含量。 最终检测结果显示到UI界面上同时上传到服务器数据库中, 可通过计算机端进行远程查询实现数据共享和信息化管理。 采用正常人血清样本作为测量试剂, 进行了重复性实验, 实验表明, CV值在0～8.30%之间, 其中T线的CV值仅为3.45%。 将含有IgG与IgM抗体的溶液, 利用梯度稀释法得到一系列不同质量浓度的样品溶液进行线性度实验, 采用线性度最小二乘法对检测结果进行曲线拟合, 拟合系数为0.997 5。 最后, 通过新冠疫苗血清抗体检测的实验表明, 检测仪的阳性检出率为75%。 该检测仪结构精巧、 功耗低、 操作简便、 性能良好, 可作为辅助手段有效提高新型冠状病毒感染的阳性检出率。

Nucleic Acid Testing (NAT) has become the “gold standard” for diagnosing SARS-Cov-2 infections in China. However, NATis affected by factors such as the disease course, specimen collection, the testing process, which are prone to false positives and missed diagnoses. The detection of SARS-Cov-2-specific IgM and IgG antibodies in serum has been used as an auxiliary method for SARS-Cov-2 detection, which can remedy the “false negative” shortcomings of NATand improve the positive rate of detection. A low-cost portable device is proposed in the paper for SARS-Cov-2 IgM and IgG antibody quantitative measurement. The device comprises a CPU signal processing module, a light source driver module, a multi-spectral detection module, a power supply module, and a display storage and communication module. Fluorescence immunochromatography technology combines the IgM and IgG antibodies in the sample to be tested with the quantum dots and trapsthem on the T line of the test strip. The light source driver module with a square-wave modulation is utilized to simulate the ultraviolet LED. Consequently the emitted ultraviolet light illuminates the T line and C line of the immunofluorescence chromatography test strip through a roof-shaped optical system. The quantum dot marker is excited by the light source to emit red fluorescence, and then the red fluorescence is captured by the multi-spectral detection module passing through the narrow-band filter. Then, the multi-spectral signal is subjected to the FFT transformation in the CPU to obtain its spectral feature. The ratio of the feature of the signal band and the reference band is applied for normalization processing to eliminate the background and environmental interference signal and to calculate the fluorescence intensity. The final detection results are displayed on the UI and uploaded to the server database, and data sharing and information management can be realized through a remote query on the computer. Therefore, the contents of IgM and IgG antibodies are determined according to the calibration coefficient of the feature ratio. Repeated experiments have been carried out using normal human serum samples as measurement reagents. The experimental results show that the CV value ranges from 0 to 8.30%, among which the CV value of the T line is only 3.45%. Two types of solution containing IgG and IgM antibodies are used to prepare a series of sample solutions with different mass concentrations using the gradient dilution method for the linearity experiment.The result is fitted by the least square method with a fitting coefficient of 0.997 5. Finally, the serum antibody test of the SARS-Cov-2 vaccine shows that the positive detection rate is up to 75%. The device has a tiny structure, low power consumption, simple operation and good performance. Therefore, it can be applied as an auxiliary means to improve the positive detection rate of SARS-Cov-2 infection effectively.