Objective To establish a droplet digital PCR(ddPCR)method for detecting the Septin9 gene methylation in colorectal cancer(CRC)and evaluate its performance.Methods Specific primers and probes were designed for the methylation of Septin9 gene.The reaction conditions of ddPCR for Septin9 gene methyl-ation detection were optimized,including primer and probe concentrations,annealing temperature and cycle number.A ddPCR method to detect the methylation of Septin9 gene was established.The linearity,sensitivi-ty,specificity,precision,accuracy and clinical diagnostic accuracy of the established method were evaluated by detecting methylation reference materials and clinical samples.Results The optimal concentrations of primers and probes were 500 nmol/L and 200 nmol/L,respectively.The optimal annealing temperature was 56℃and the optimal number of cycles was 45.The linearity test showed good linearity in the range of 5-104 copy/re-action,and the preset detection limit of Septin9 gene methylation concentration detected by ddPCR was 0.422%,which could specifically identify Septin9 gene methylation positive control.In precision evaluation,the coefficients of variation of high concentration and low concentration reference materials were 1.340 0%and 3.330 0%,which met the relevant requirements.The results of accuracy test showed that the positive co-incidence rate and negative coincidence rate of 10 repeated tests of methylation quality control samples of 3 batches were both 100%.The results of clinical samples showed that the sensitivity and specificity of ddPCR detection of Septin9 gene methylation in CRC group were 82.61%(95%CI 66.10%—99.10%)and 78.38%(95%CI 65.20%—91.60%),respectively.The area under the curve was 0.881 3(95%CI 0.784-0.978 6).Conclusion The ddPCR method for detection of Septin9 gene methylation in CRC has high sensitivity,speci-ficity,precision,accuracy and clinical diagnostic accuracy.It can provide a reliable technical means for early di-agnosis,monitoring and treatment of CRC.

Objective:The quality of domestic diagnostic accuracy research was evaluated to explore the quality level of domestic diagnostic accuracy research based on Standards for Reporting of Diagnostic Accuracy 2015 (STARD2015).Methods:The Chinese core journals of CNKI and Wanfang Database were searched, and research literature on diagnostic accuracy published from 2017 to 2022 were collected. The main search terms are diagnostic test, sensitivity, specificity, receiver operating characteristic (ROC) curve, etc. The literature was selected according to the inclusion criteria, and the quality of the included literature was evaluated independently by two reviewers, and the conformity rate of the STARD2015 report and the STARD2015 article was calculated. The report quality of the literature was divided into three levels (low, medium and high) according to the conformity rate of the STARD2015 report. The proportion of literature at each level and the proportion of literature at medium and high level in each year were counted. According to quality analysis on the contents of the included articles, articles were divided into standardized reports and unstandardized reports. Intragroup correlation coefficient ( ICC) was used to analyze the consistency of two reviewers. The trend Chi-square test was used to analyze the trend of the proportion of medium and high level literature in each year. One-way analysis of variance was used to compare the coincidence rates evaluated by STARD2015 for each year. Results:A total of 6 771 studies on diagnostic accuracy published from 2017 to 2022 were included. The compliance rate sccording to STARD2015 was 39.56%±4.90%, and the reported compliance rate ranged from 17.65% to 64.71% (the number of reported items ranged from 6 to 22), and 93.53% (6 333/6 771) literatures were in the middle level. Compliance rate of STARD2015 reports varied significantly among different years ( F=25.023, P<0.01), and the compliance rate of 2021 was significantly higher than that of other years ( P<0.01). The proportion of medium and high level literatures according to STARD2015 showed an increasing trend ( χ 2=14.099, P<0.01). The reporting situation of each item varied significantly, and the conformity rate of items raned from 0 to 100%. According to report item, non-standard report rate was 10.34% (569/5 503) for item 6, 4.15% (277/6 677) for item 8, 21.84% (1 447/6 626) for item 20, 66.67% (24/36) for item 22, and 26.03% (877/3 369) for item 26. Conclusions:The overall report quality of published domestic literature on diagnostic accuracy from 2017 to 2022 is at a medium level according to STARD2015, and the reports conformity rate of each item vary significantly, indicating significant knowledge gap on STARD2015 among domestic researchers. The promotion of STARD2015 needs to be strengthened.