OBJECTIVETo describe and evaluate a double-antigen sandwich ELISA for detecting human immunodeficiency virus type 1/2 (HIV-1/2) specific antibodies.

METHODSThe peptides gp41.1(sp1), gp41.2(sp2), gp120(sp3) and p24(sp4) of HIV-1 and gp36(sp5) of HIV-2 were artificially synthesized. Then sp1, sp3, sp4 and sp5 were used as coating antigens; sp1, sp2, sp4 and sp5 labeled with HRP were used as conjugates in this sandwich ELISA.

RESULTSThe specificity and sensitivity of the assay were both 100% in detecting anti-HIV of 40 control sera of the second generation panel, higher than indirect ELISA (specificity 90% and sensitivity, 65%, respectively). All of 210 sera from individuals with other diseases were negative for anti-HIV. The consistency rate was 100% when our sandwich ELISA and Abbott HIVAB were used to detect anti-HIV in 90 healthy blood donors and 88 HIV infected individuals.

CONCLUSIONSThe results showed that this sandwich ELISA for detection of anti-HIV is specific, sensitive and convenient, and it is suitable for screening blood donors and detecting HIV infection.

Enzyme-Linked Immunosorbent Assay ; methods ; HIV Antibodies ; blood ; HIV Infections ; blood ; virology ; HIV-1 ; immunology ; HIV-2 ; immunology ; Humans

Objective To propose the blood detection strategies for human immunodeficiency virus (HIV) among blood donors, and provide reference for the detection, early diagnosis and transmission blocking of HIV. Methods A total of 117 987 blood samples from blood donors were screened using the third- and fourth-generation ELISA HIV detection reagents. Western blot analysis was used to verify the reactive results of the third-generation reagent alone, or both the third-generation and fourth-generation reagents. HIV nucleic acid test was carried out for those with negative test results of the third- and fourth-generation reagents. For those with positive results of the fourth-generation reagent only, nucleic acid test followed by a confirmatory test by Western blot analysis was carried out. Results 117 987 blood samples from blood donors were tested by different reagents. Among them, 55 were tested positive by both the third- and fourth-generation HIV detection reagents at the same time, accounting for 0.047% and 54 cases were confirmed HIV-positive by Western blot analysis, and 1 case was indeterminate, then turned positive during follow-up testing. 26 cases were positive by the third-generation reagent test alone, among which 24 cases were negative and 2 were indeterminate by Western blot analysis. The band types were p24 and gp160 respectively detected by Western blot analysis, and were confirmed to be HIV negative in follow-up testing. 31 cases were positive by the fourth-generation HIV reagent alone, among which 29 were negative by nucleic acid test, and 2 were positive according to the nucleic acid test.Western blot analysis was used to verify that the two cases were negative. However, after 2~4 weeks, the results turned positive when the blood sample was retested by Western blot analysis during the follow-up of these two cases. All the specimens that were tested negative by both the third- and fourth-generation HIV reagents were validated negative by HIV nucleic acid test. Conclusion A combined strategy with both third- and fourth-generation HIV detection reagents can play a complementary role in blood screening among blood donors. The application of complementary tests, such as nucleic acid test and Western blot analysis, can further improve the safety of blood supply, thus contributing to the early diagnosis, prevention, transmission and treatment of blood donors potentially infected by HIV.
Humans ; HIV Infections/diagnosis* ; HIV Antibodies ; Blood Donors ; HIV-1 ; Blotting, Western ; Nucleic Acids

We compared the performance of three screening kits for the detection of anti-HIV in 187 samples; Enzygnost Anti-HIV 1/2 Plus, ABBOTT TESTPACK HIV- 1/HIV-2 & SERODIA. HIV- 1/2. Four samples, 3 serums and 1 CSF, from 2 patients were repeatedly reactive in all three screening kits and 2 serum specimens were confirmed positive(HIV-1) by the western blot assay. The sensitivity and specificity of all three screening kits were 100% and 98.9%, respectively. In Korea, the cause of AIDS is mostly HIV-1 and the prevalence is very low. So, all three screening kits were useful for the detection of anti-HIV from patients and blood donors. But the use of screening kit for the detection of anti-HIV-1, anti-HIV-2 and anti-HIV-I subtype O will be needed for the decrement of false negative rate because HIV infection has been increased, especially, HIV-2 infection and pediatric AIDS patient by vertical transmission were also reported, currently.
Antibodies* ; Blood Donors ; Blotting, Western ; HIV Infections ; HIV* ; HIV-1 ; HIV-2 ; Humans ; Korea ; Mass Screening* ; Prevalence ; Sensitivity and Specificity

OBJECTIVETo study whether plasma viral load testing is helpful to exclude ones free from Human immunodeficiency virus (HIV) infections from suspects in HIV antibody detections.

METHODS19 Specimens, which showed disconcordant results of the two HIV EIA testing (S/CO < 6) and indeterminated results of Western blot (WB) test, were selected. Viral load of the specimens were detected. A six-month follow up survey in detecting HIV antibody was conducted in these subjects.

RESULTSNone of these 19 cases was observed to be positive HIV viral loads and there was no any progress in WB bands development during the follow-up period. The possibility of HIV infection could be excluded.

CONCLUSIONWhen the specimens react with very low intensity in both EIA and WB, negative viral load result is conducive to exclude negative subjects from suspects in HIV antibody detections.

AIDS Serodiagnosis ; HIV Antibodies ; blood ; HIV Infections ; blood ; diagnosis ; Humans ; Viral Load

Determine HIV-1/2, Chembio HIV-1/2 STAT-PAK and PenTest are simple/rapid tests for the detection of antibodies to HIV-1 and HIV-2 in human whole blood, serum and plasma samples. The assay is one step and the result is read visually within 15 minutes. Using 92 known HIV-1 reactive sera and 108 known HIV-1 negative sera, the 3 HIV tests correctly identified all the known HIV-1 reactive and negative samples. The results indicated that Determine HIV-1/2, Chembio HIV-1/2 STAT-PAK and PenTest HIV are as sensitive and specific (100% concordance) as Microparticle Enzyme Immunoassay. The data indicated that these 3 HIV tests are effective testing systems for diagnosis of HIV infection in a situation when the conventional Enzyme Immunoassay is not suitable.
*AIDS Serodiagnosis ; HIV Antibodies/*blood ; Sensitivity and Specificity ; Time Factors

OBJECTIVETo explore the follow-up visit, outcome and auxiliary diagnosis method on the cases with indeterminate antibody level measured by Western blotting as well as the related biological factors.

METHODSThe cases with indeterminate result were followed up according to the National Guideline for Detection of HIV/AIDS (2009) and samples were collected for HIV antibody detection, p24 antigen and nucleic acid were detected as a supplementary diagnosis at the same time. The samples were also be detected for HBV, HCV, TP, HTLV-I/II, ANA, and AFP, and the results were compared to that of screened positive and confirmed negative cases.

RESULTSA total of 73 were followed up successfully and taken a second HIV test, 25 cases were tested positive and 48 were tested negative for HIV during the follow-up period. For the 25 HIV positive cases, the HIV seroconversion rate was 100.00% at any time point when the interval between the first and returning detection was longer than 1 week. The major Western blotting bands for the cases with indeterminate result were p24 and gp160 and it was different between HIV positive and negative cases in Western blotting band profiles. The consistency and sensitivity of nucleic acid detection were higher than 90.00%, and were higher than that of p24 antigen (69.09% (38/55) and 27.27% (6/22)) (χ(2)(consistency) = 6.875, χ(2)(sensitivity) = 18.893, P < 0.05). The positive rates of ANA and AFP of indeterminate cases excluded from HIV infection were 20.83% (10/28) and 6.25% (3/48) and higher than that of screened positive and confirmed negative cases (0.00%), the difference had statistic significance (χ(2)(ANA) = 19.430, χ(2)(AFP) = 5.520, P < 0.05).

CONCLUSIONIt is critical to get timely diagnosis for the indeterminate cases according to the new national guideline for detection of HIV/AIDS. Nucleic acid detection has higher application value as auxiliary diagnosis for HIV infection than p24 antigen. The increased levels of ANA and AFP may be the factors resulting in the nonspecific indeterminate results.

Antibodies, Antinuclear ; blood ; Female ; Follow-Up Studies ; HIV Antibodies ; blood ; HIV Infections ; diagnosis ; immunology ; Humans ; Male ; alpha-Fetoproteins ; analysis

BACKGROUND: Many immunochromatography (ICA) kits for anti-human immunodeficiency virus type (HIV) antibody (Ab) have been introduced to improve the accessibility of HIV Ab tests. However, qualified evaluation reports for HIV rapid tests are not enough to validate their performances. Metaanalysis for the performances of the HIV Ab rapid tests was performed in this study. METHODS: PubMed database was searched with combination of search terms, 'human immunodeficiency virus', 'HIV Ab', 'rapid test', 'immunochromatography', 'performance', 'sensitivity', and 'specificity'. Criteria of inclusion were performance studies for HIV ICA kits with serum or EDTA whole blood. Methodological qualities were evaluated with standards for reporting of diagnostic accuracy studies (STARD) checklists by two investigators. Homogeneity among selected studies was evaluated and then pooled sensitivity and specificity were calculated. Positive and negative predictive values were simulated with presumed HIV prevalence in Korea. RESULTS: Twenty-three studies were selected from 12 high-qualified papers with STARD checklists. The performance of 23 studies were found to be heterogeneous (P<0.1) and random effect model was used. Pooled sensitivity was 99.71% (95% CI: 99.45-99.97%) and pooled specificity was 99.27% (95% CI: 98.83-99.70%). With HIV prevalence of 0.03%, positive and negative predictive values were presumed to be 3.936% and 99.999%, respectively. CONCLUSIONS: This meta-analysis for HIV ICA rapid tests showed good performance. In consideration of low positive predictive values of HIV rapid tests, confirmation by enzyme immunoassay or Western blot is still needed. This study would be helpful in evaluating and establishing proper performance guideline for those kits not fully evaluated.
HIV Antibodies/*blood/immunology ; HIV Infections/*diagnosis ; Humans ; Reagent Kits, Diagnostic ; Sensitivity and Specificity

OBJECTIVEThis study was to compare the performance of three HIV antibody confirmatory assay kits in confirming early HIV infection.

METHODSFive HIV antibody-positive plasma specimens were ten-fold serially diluted and then detected by ELISA. The above diluted specimens were detected with the following three HIV antibody confirmatory assay kits to analyze their sensitivity, including Wantai-RIBA (Recombinant immunoblot assay, Beijing Wantai Biological Pharmacy, China), MP-WB (HIV Blot 2.2 WB, MP Biomedicals Asia Pacific Pte. Ltd., Singapore) and INNO-LIA (INNO-LIA(TM) HIV I/II Score, Innogenetics N.V., Belgium), respectively. These kits were further used to detect 48 ELISA-reactive specimens from 11 sets of HIV seroconversion specimens (a total of 48 samples) which were previously detected as HIV antibody-positive by ELISA.

RESULTSWhen 5 samples were diluted to 100 fold, Wantai-RIBA still can detect them positive. Among the 48 HIV antibody-positive specimens detected with ELISA, the confirmation positive rate for Wantai-RIBA, MP-WB and INNO-LIA were 97.92% (47/48), 81.25% (39/48) and 91.67% (44/48), respectively. There was statistically significant difference between the confirmatory results of Wantai-RIBA and MP-WB (χ(2) = 6.13, P < 0.05), as well as between those of INNO-LIA and MP-WB (χ(2) = 5.48, P < 0.05); however, there was no statistically significant difference between those of Wantai-RIBA and INNO-LIA (χ(2) = 1.33, P > 0.05). For other six HIV seroconversion panels containing indeterminate specimens, the average seroconversion period of time for Wantai-RIBA, MP-WB and INNO-LIA were 0.7, 13.3 and 3.7 days, respectively.

CONCLUSIONCompared with MP-WB, Wantai-RIBA and INNO-LIA could reduce the window period to confirm early HIV infection.

Early Diagnosis ; HIV Antibodies ; blood ; HIV Infections ; diagnosis ; Humans ; Reagent Kits, Diagnostic

OBJECTIVETo establish and evaluate an Enzyme Immunoassay diagnostic kit combined with anti-HIV1/2 antibody and P24 antigen for shortening the examination window period of HIV infection in HIV laboratory diagnosis.

METHODSThe enzyme-linked reaction plates was coated by anti-HIV P24 monoclonal antibody and HIV 1/2 antigen. Labeling HIV1/2 antigen and anti-HIV P24 polyclonal antibody with horseradish peroxidase, setup an integrated ELISA kit for detecting anti-HIV-1/2 antibody and HIV P24 antigen, and evaluate the specificity and sensitivity of this kit.

RESULTSThe sensitivity of testing P24 antigen was up to 0.2 ng/ml. 78 serum samples of patients with AIDS, 85 serum samples of healthy people were compared with Abbott EIA kit, the coincidence was 100%. 12 051 sera from normal persons and patients were examined, the sensitivity of 100 %and specificity of 99.62 %, respectively.

CONCLUSIONThe anti-HIV1/2 antibody and HIV P24 antigen can be measured at the same time using this EIA kit, while the examination window period of HIV infection is shortened. Thus, the method is suitable for laboratory diagnosis and epidemiological investigation.

Enzyme-Linked Immunosorbent Assay ; HIV Antibodies ; blood ; HIV Core Protein p24 ; blood ; HIV-1 ; immunology ; HIV-2 ; immunology ; Humans ; Reagent Kits, Diagnostic

OBJECTIVETo study the incidence and risk factors of HIV and syphilis seroconversion among men who have sex with men (MSM) in Beijing.

METHODSA total of 550 MSM were recruited on the basis of community and followed up after 6 and 12 months in Beijing. Each subject was investigated by only one investigator at one time to collect information on demographics and behaviors. Blood samples were collected to test HIV and syphilis seroconversion. ELISA was used for screening test, west blotting (WB) and Particle agglutination were used for confirmatory test.

RESULTSA total of 550 MSM investigated, among which 4.5% (25/550) were HIV-positive and 29.3% (161/550) were syphilis-positive. For 525 HIV-negative MSM, 87.0% (457/525) retained during the 12-month investigation. Seroincidence for HIV and syphilis were 3.37/100 person-years (95%CI = 1.66 - 5.08) and 9.32/100 person-years (95%CI = 5.87 - 12.77) respectively. HIV seroconversions for those who performed and did not perform rectal douching after homosexual anal intercourse in the past 3 months were 7.11/100 and 0.76/100 person-years respectively. Multivariate Cox regression analysis revealed that rectal douching after homosexual anal intercourse in the past 3 months (HR = 9.23, 95%CI = 2.08 - 40.88) was significantly associated with HIV seroconversion. Syphilis seroconversions for those who met male sex partners in parks, public washrooms or bathhouses in the past 3 months were 41.77/100 and 7.97/100 person-years respectively. Syphilis seroconversions for those who performed and did not perform rectal douching after homosexual anal intercourse in the past 3 months were 16.17/100 and 4.92/100 person-years respectively. In the past 3 months, meeting male sex partners in parks, public washrooms or bathhouses (HR = 4.67, 95%CI = 1.77 - 12.34) and performing rectal douching after homosexual anal intercourse (HR = 3.09, 95%CI = 1.40 - 6.83) were significantly associated with syphilis seroconversion.

CONCLUSIONThe seroconversions of HIV and syphilis during the follow-up visits in this MSM cohort study in Beijing were very serious, and that the associated factors for seroconversions were rectal douching after homosexual anal intercourse and meeting male sex partners in parks, public washrooms or bathhouses.

Adolescent ; Adult ; Antibodies, Bacterial ; blood ; China ; epidemiology ; HIV ; immunology ; HIV Antibodies ; blood ; HIV Infections ; blood ; epidemiology ; HIV Seropositivity ; blood ; epidemiology ; Homosexuality, Male ; Humans ; Incidence ; Male ; Risk Factors ; Sexual Behavior ; Syphilis ; blood ; epidemiology ; Treponema pallidum ; immunology ; Young Adult