The Methodology Evaluation Of Human Immunodeficiency Virus Rapid Diagnostic Tests In Oral Mucosal Transudate For Self-testing

ObjectiveTo construct the evaluation panels of HIV OMT RDTs,and parallel evaluate performances of 6 HIV OMT RDTs in the Reference Laboratory.To assess whether key messages from instructions for use would be accurately understood,and evaluate the ability of accurate interpretation of pre-made test-results and the ability and accuracy of HIVST in MSM on site.MethodsThe optimum diluent and the optimum dilution ratio were explored in the Reference Laboratory.And plasma samples and OMT samples of HIV infectors were simultaneously collected to verify whether the optimum dilution ratio is appropriate.Simulated samples of OMT prepared by diluting multiple anti-HIV positive plasma sample and HIV negative plasma sample to the optimum dilution ration with the optimum diluent were used to construct the Lab basic panel,the Lab analytical specificity panel,the Lab dilution panel,the Lab precision panel.4 evaluation panels constructed and HIV antibody panel for oral fluid rapid test were tested with 6 HIV OMT RDTs.Results were visually read and detected by the reader which got GOD value.After signing the informed consent,subjects in Sichuan Province and Guangxi Zhuang Autonomous Region filled out the basic information and the questions based on the key messages,interpreted pre-made test-results and used HIV OMT RDTs for HIVST without the guidance from investigators.Meanwhile investigators carefully observed the operations,filled right or wrong in the abservation table and interpreted HIVST result.Finally,Investigators tested subjects by using HIV Blood RDTs and interpreted the correspond results.ResultsThe optimum diluent and the optimum dilution ration of simulated samples were respectively PBS containing 15%inactivated chicken serum and 210.According to visually read,for reagent A to F,consistencies of positive and negative reference,sensitivities and specificities were all 100%;analytical specificities were greater than or equal to 95.12%;and analytical sensitivities were greater than or equal to 3/5.Within-lot precision of reagent D was better than that of other reagents.Linear range of reagent F was ranged from 28 to 214.And reagent F didn't appeare the prozone.Based on GOD values,for reagent A to E,consistencies of negative reference,specificities and analytical specificities were all 100%;consistencies of positive reference were greater than or equal to 95%;sensitivities were at least 92.5%;analytical specificities were greater than or equal to 95.12%;analytical sensitivities were at least 3/5;linear ranges were 28-216,27-217,26-216,26-215 and 25-212 respectively;and within-run precisions were ranged from 4.91%to 34.28%.Reagent A,B,C and E appeared the prozone,and reagent D didn't.GOD values of reagents A-E for different evaluation panels that were tested with non-parametrical test have a statistical difference,P<0.05.Among 305 subjects that were effectively investigated,74.1%self-reported homosexuality;78.7%was han nationality;13.1%married;93.4%at least graduated from high school education;62.6%had stable jobs;the average monthly income of 72.5%was beyond 2,000 RMB;25.2%had HIVST history;fingertip blood test results of 17.7%were reactive.The accuracies of key messages from precautions,the procedure and interpretation of test result of instructions for use ranged from 3.9%(12/305)to 98.4%(300/305).When subjects faced with the results of the reactive self-test,the ratio of selection to the local CDC/Hospital was 59.6%(223/374).The accuracies of interpretation of pre-made ranged from 44.9%(137/305)to 91.5%(279/305).The accuracies of the steps of HIVST ranged from 36.7%(112/305)to 96.7%(295/305).The accuracies of HIVST were 92.5%(282/305).And no touch with middle part of test paper and inserting test paper with the arrow pointing down were associated with the accuracy of HIVST.ConclusionsThe performances of 6 HIV OMT RDTs meet the requirements of HIV antibody panel for oral fluid rapid test.They have high sensitivities and specificities,and different liner ranges and prozones.When one sample is repeatedly tested with one kind of HIV OMT RDTs,their color intensities were basically uniform.No false reactivity was found in 4 HIV OMT RDTs.And 2 HIV OMT RDTs had false reactivities when testing OMT collected after eating.The ability of MSM population correctly understanding of key messages from precautions,the procedure and interpretation of test result of instructions for use was low.In the face of reactive results of HIVST,beyond 50%MSM selected to the local disease prevention and control center or hospitals.MSM population may have the lower ability of correctly interpreting results of HIVST,such as the average accuracy of reactivity results being about 50%.Each step of HIVST went wrong.When MSM use HIV OMT RDTs for self-testing,the accuracy is 92.5%,which is influenced by two operation steps including "no touch with middle part of test peper" and "the test strip with the direction of arrows down being inserted to the test tube".