RESUMEN
【Objective】 To explore the correlation between serological screening of human T-lymphotropic virus antibodies (anti HTLV) and Western blot(WB) confirmatory tests among blood donors, so as to explore the infection status of HTLV Ⅰ/Ⅱ in Guangzhou. 【Methods】 The anti HTLV Ⅰ/Ⅱ enzyme-linked immunosorbent assay(ELISA) kit was used to screen voluntary blood donors from Guangzhou Blood Center from July 2016 to August 2022. WB was used to confirm 395 reactive blood samples by ELISA. The correlation between the S/CO values of anti HTLV Ⅰ/Ⅱ ELISA reagents and the confirmatory test was analyzed using ROC curves. 【Results】 The results showed that 25 out of 395 initially screened reactive blood donor samples were confirmed as HTLV positive by WB, while 16 were uncertain. ROC curve analysis showed a correlation between the S/CO values by ELISA and the confirmatory test results: the S/CO value at the highest Youden index was 3.789, which was the optimal threshold. The S/CO value had a certain correlation with the predicted positive rate of confirmatory results (P<0.05): the larger the S/CO value, the higher the predicted positive value. The overall prevalence of HTLV in Guangzhou is relatively low. 【Conclusion】 The prevalence of HTLV among blood donors in Guangzhou is low.Since the false positive rate of HTLV Ⅰ/Ⅱ antibody by ELISA serological screening is high, the confirmatory testing is particularly important.
RESUMEN
【Objective】 To compare the results by minipool and individual NAT on blood samples with HBsAg detection S/CO value between 0.25-0.90 by ELISA, in order to re-evaluate the safety of NAT for such negative samples with high HBsAg S/CO value and provide references for the optimization of detection process. 【Methods】 A total of 30 blood samples which were non-reactive for HBsAg by ELISA twice and with the S/CO value of any reagent between 0.25-0.90 (defined as " high S/CO value negative" ) from our center from February to October 2020 were collected, and minipool test of 6 samples and individual test were performed in parallel. 11 samples which were negative by minipool tests but positive by individual test were submitted to repeated NAT minipool tests, and the results of each test were recorded and analyzed. 【Results】 The median S/CO values of the 30 samples by two ELISA reagents were 0.565 and 0.320, respectively, and the differences were statistically significant (P 0.05). 【Conclusion】 The NAT-yield of samples with high ELISA HBsAg S/CO value was high in individual test and low in minipool test, and the NAT-yield in minipool test could be improved by repetitive test. Therefore, the safety of NAT for samples with high HBsAg S/CO value should be re-evaluated as minipool test is dominant in blood stations. Individual NAT test is recommended for such samples currently as there is no any other more sensitive detection approaches.