| BackgroundFourth-generation HIV assays have been implemented worldwide as a screening test for many years.It is reported that the performance of the assays may vary significantly in different demographic factors and geographic regions.As understanding the performance of the fourth-generation assay in low HIV prevalence region is pivotal to interpret the test result correctly.In this study,we set to analyze the application of Architect HIV Ag/Ab Combo Reagent Kit and Elecsys(?)HIV combi PT assay.Methods1.Retrospective analysis was used to evaluate the application of two kinds of fourth-generation HIV assays in our laboratory from December 2009 to December 2017.(1)To analyze the positive/false positive detection of the two reagents,the distribution of the results and so on;(2)to analyze the characteristics of the HIV positive patients,and(3)to analyze the characteristics of the HIV false positive patients.2.The precision,detection sensitivity,coincidence rate and interference test were analyzed,and the potential factors for the false positive results of the two reagents were discussed.Results1.A total of 98537 specimens were detected by Architect HIV Ag/Ab Combo Reagent Kit with a specificity of 99.90%(95%CI:99.88%-99.92%);a total of 172931 specimens were detected by Elecsys(?)HIV combi PT assay,and the specificity was 99.81%(95CI:99.79%-99.83%).The false positive rate of Abbott reagent was significantly lower than that of Roche reagent(0.10%vs.0.19%,x2=31.50,P<0.01).The false positive results of Abbott(S/CO)and Roche(COI)reagents were mainly within 10,and the median values were 2.08 and 1.85,respectively,which were significantly smaller than the results of "Indeterminate" and "True positive".2.The number of HIV screening cases increased year by year,but the positive detection rate remained stable,with a total positive rate of 1.03‰.The ratio of male to female was 3.91:1 in HIV positive patients,mainly in the 21-50 years group.3.Abbott reagent detected 96 false positive cases,the ratio of male to female was 1.18:1,and Roche reagent detected 320 false positive cases,the ratio of male to female was 1:1.The sex distribution of the false-positive population in different age groups changed significantly.The false positive population is mainly under the following diseases,such as infectious diseases,malignant tumors,cardiovascular diseases.4.Precision analysis of two reagents showed that CVs were less than 7%.And the HIV-1 antibody detection limit is between 0.5-1NCU/ml by Roche reagents,better than Abbott reagents.While detection limit of p24 antigen is between 0.625-1.25U/ml by both reagents.The coincidence rate of both reagents which evaluated by quality control samples were 100%.Lipemia,jaundice,hemolysis and rheumatoid factor did not interfere with the two HIV reagents.5.The false positive rate between the two reagents was not statistically significant(Abbott,male vs.female =0.10%vs.0.09%,x2=0.55,P>0.05;Roche,male vs.female=0.18%vs.0.19%,X2=0.05,P>0.05).In addition,the background values of the two reagents were similar to those of the HIV negative population,but the results of the Roche reagent were more centralized and the background homogeneity was better.Abbott and Roche reagents detected the false positive samples respectively,and the specificity were 94%(95CI:83.45%,98.75%)and 92.86%(95CI:66.13%,99.82%).ConclusionBoth of the fourth generation HIV test reagents have good detection performance and are suitable for use as screening reagents.However,false-positive events occur occasionally.In particular,the false positive rate of Roche reagent is higher than that of Abbott.In the clinical application process,HIV suspected samples should be managed according to "National Guideline for Detection of HIV/AIDS". |
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