Evaluation of a simultaneous HIV antigen and antibody detection test in Korean population

Current diagnosis of human immunodeficiency virus (HIV) infection relies on the detection of anti-HIV antibodies by enzyme-linked immunosorbent assay (ELISA). Recently, kits detecting both p24 antigenemia and anti-HIV/anti-HIV2 antibodies have been developed. Thus, it is necessary to compare those kits developed as such. The aim of this study was to evaluate the diagnostic efficiency of a simultaneous detection test of p24 antigen and anti-HIV1/2 antibodies in a low prevalence area. Eight hundred and four randomly selected sera proven negative for HIV infection and 110 sera from 54 patients diagnosed as HIV infected, obtained between 1999 and 2000, were used for this study. One commercial lot of panels composed of consecutive sera obtained from known HIV-infected patient was included. Anti-HIV1/2 antibodies were detected by two different commercial ELISA kits, one from Korean and the other from German manufacturer. P24 antigen test was performed by ELISA. The simultaneous HIV antigen and antibody detection test was carried out. In the meantime, HIV RNA PCR and anti-HIV and anti-HIV2 western blot assays were also performed to confirm the test results in cases the test results didn't agree. The simultaneous detection kit showed 100% sensitivity and 99.6% specificity. Furthermore, the test displayed the possibility of earlier diagnosis than conventional anti-HIV1/2 ELISA with the results obtained from a group of consecutive panel sera infected with HIV. From these results, we concluded that the simultaneous HIV antigen and antibody detection test can be applied as a substitute clinical screening test in the place of conventional anti-HIV1/2 ELISA, and there is the probable benefit of early diagnosis.     

Negative results of a rapid antibody test for HIV in a 16-month-old infant with AIDS

In a 16-mo-old infant born to an HIV-infected mother, repeatedly negative results of a HIV rapid antibody test had been reported during the past 6 mo. The infant presented with several HIV-defining illnesses and HIV RT-PCR testing confirmed the presence of HIV infection. There are at least 2 possible explanations for the child's false-negative rapid HIV test results: First, his primary antibody production may have been suppressed by the presence of maternal IgG antibodies. Second, his mother was highly immunosuppressed, so that the low level of maternally derived IgG was only detected by HIV-EIA and Western blot. Our data suggest that the HIV rapid antibody test may not be sufficiently sensitive to detect HIV antibodies in infants aged <18 mo.     

Young age a predictor of weak reactivity in a rapid antibody test in infants infected with HIV

In a resource‐constrained African setting, children suspected of being infected with HIV are often screened with rapid antibody tests prior to definitive diagnosis with viral genome detection. It has previously been shown that a rapid antibody assay such as the Capillus? HIV‐1/HIV‐2 test may have a high false‐negative rate in infants. In this study CD count and percentage, HIV‐1 viral load, antigen‐specific reactivity, and age was explored as predictors of negative or low antibody reactivity by this assay. Young age was found to be the only factor associated significantly with low antibody reactivity. This phenomenon appeared to be specific to HIV since no such age association was found for antibody reactivity to tetanus toxoid. Rapid assays only validated in adults should therefore be used with utmost caution in young infants since this may lead to high rates of false‐negative results. J. Med. Virol. 82:1314–1317, 2010. © 2010 Wiley‐Liss, Inc.     

Evaluation of pooled rapid HIV antibody screening of patients admitted to a San Diego Hospital

Current HIV screening guidelines in the United States recommend expanding the scope of HIV screening to include routine screening in health care settings; however, this will require increased resources. Since testing of pooled samples can decrease costs, the test characteristics of pooled rapid antibody testing were determined and optimal pool sizes were estimated for populations with HIV prevalence ranging from 0.25% to 10%. Based on these results, pooled testing methods were evaluated for screening patients admitted to hospital in San Diego, California. Evaluation of pooled antibody testing on samples collected from individuals with known HIV infection found only a modest reduction in sensitivity. These false negative results were only found among samples with very low optical density readings (<0.125 by the ADVIA Centaur? HIV assay). These readings are considered as HIV negative by the ADVIA Centaur? HIV assay, and therefore likely correspond to samples collected during acute infection. Further evaluation of pooled testing of samples collected from individuals during recent infection, found that mini-pool testing of five samples detected HIV antibody in 86% of samples taken within 60 days of the initial infection and 92% of samples taken within 90 days of the initial infection. Based on estimations of optimal pool sizes for low prevalence populations, it was decided to evaluate mini-pools consisting of 10 samples to screen the study's hospitalized patients. During this evaluation, the HIV prevalence among hospitalized patients was 0.8%, and the 10 sample mini-pool testing had 100% sensitivity and specificity. Additionally, pooled testing resulted in an 84.5% reduction in the number of rapid HIV antibody tests needed, as compared to testing each sample individually. Even when incorporating the increased costs of technician time, mini-pooled tested would have resulted in a net savings of 8760 USD for the 523 samples tested in the study. Taken together, these results indicate that pooled rapid antibody testing may reduce substantially the costs for HIV screening in low prevalence populations without a loss in accuracy.     

HIV抗体纳米免疫磁珠快速检测试剂的研制

目的 研制一种用纳米免疫磁珠层析技术用以检测HIV抗体的快速诊断试剂.方法 运用碳二亚（EDC）将重组的HIV抗原gp41、gp36偶联到200 nm的超顺磁纳米颗粒上,在硝酸纤维素（NC）膜上包被gp41、gp36抗原,制备成免疫层析检测卡,然后对检测卡进行性能分析评估.结果 对HIV抗体国家参考品血清盘（胶体金类）检测,符合要求;对20份HIV抗体阳性和600份抗体阴性临床血清检测,灵敏度为100%,特异性为98.5%.检测卡室温保存12个月性能稳定.结论 研制出一种纳米免疫磁珠HIV抗体检测试剂,具有检测简便、快速、稳定性好和适于现场检测等特点.     

HIV抗体纳米免疫磁珠快速检测试剂的研制

目的 研制一种用纳米免疫磁珠层析技术用以检测HIV抗体的快速诊断试剂.方法 运用碳二亚(EDC)将重组的HIV抗原gp41、gp36偶联到200 nm的超顺磁纳米颗粒上,在硝酸纤维素(NC)膜上包被gp41、gp36抗原,制备成免疫层析检测卡,然后对检测卡进行性能分析评估.结果 对HIV抗体国家参考品血清盘(胶体金类)检测,符合要求;对20份HIV抗体阳性和600份抗体阴性临床血清检测,灵敏度为100%,特异性为98.5%.检测卡室温保存12个月性能稳定.结论 研制出一种纳米免疫磁珠HIV抗体检测试剂,具有检测简便、快速、稳定性好和适于现场检测等特点.     

HIV抗体纳米免疫磁珠快速检测试剂的研制

目的 研制一种用纳米免疫磁珠层析技术用以检测HIV抗体的快速诊断试剂.方法 运用碳二亚(EDC)将重组的HIV抗原gp41、gp36偶联到200 nm的超顺磁纳米颗粒上,在硝酸纤维素(NC)膜上包被gp41、gp36抗原,制备成免疫层析检测卡,然后对检测卡进行性能分析评估.结果 对HIV抗体国家参考品血清盘(胶体金类)检测,符合要求;对20份HIV抗体阳性和600份抗体阴性临床血清检测,灵敏度为100%,特异性为98.5%.检测卡室温保存12个月性能稳定.结论 研制出一种纳米免疫磁珠HIV抗体检测试剂,具有检测简便、快速、稳定性好和适于现场检测等特点.     

Evaluation of a rapid technique for antibody elution

This study evaluated a new rapid acid elution technique using citric acid. This technique was compared to the commonly used digitonin acid procedure. Twenty patient or donor antibodies with specificities in the Rhesus, Kell, Kidd, or Duffy systems were used to coat red cells. Eluates produced from these cells by the citric acid procedure were equivalent or greater in volume and potency to those produced by a digitonin acid method. The citric acid procedure required five to nine minutes to complete, while the digitonin acid procedure required 28 to 44 minutes. The citric acid technique is a rapid means of producing a potent eluate.     

Detection of HCV salivary antibodies by a simple and rapid test

Hepatitis C (HCV) is common in developing countries, where blood sampling and expensive sophisticated methods for detection are less available. Hemodialysis patients have high prevalence of HCV and may resemble sick populations in developing countries in relation to immunosuppression and antibodies production. For these reasons anti-HCV antibodies were assayed in saliva of hemodialysis patients by ImmunoComb II assay that is less laborious, relatively inexpensive and easy to perform If the findings are confirmed by larger studies this method may be useful especially in developing countries. Serum and saliva samples were obtained from 37 hemodialysis patients and assayed by ImmunoComb II kit. In positive PCR patients the saliva test had 100% sensitivity, which was as good as serum anti-HCV Axsym testing. Saliva testing had a similar or better specificity than the serum method.     

Evaluation of a serum gonococcal antibody test

The authors evaluated the Gonosticon Dri-Dot system as a tool for the determination of the prevalence of gonococcal serum antibody in two female populations. This paper discusses their findings.     

Development and evaluation of a rapid neutralizing antibody test for rabies

The level of virus-neutralizing antibody, which plays a crucial role in the prevention of rabies, is determined by rabies virus (RABV) neutralizing test, which are time- and cost-consuming. In order to determine the level of neutralizing antibody in vaccinees, an easy and reliable method is needed. Based on the principle of immunochromatography, we developed a RAPINA (RAPId Neutralizing Antibody) test to determine the presence of neutralizing antibody in serum. In the RAPINA test, if neutralizing antibody equivalent to 0.5 IU/ml of serum sample are mixed with an optimal amount of inactivated RABV (iRABV) and are completely absorbed by the virus, none of the iRABV can bind with monoclonal antibody that recognizes the iRABV glycoprotein (G) on the test strip. A total of 115 human sera samples were tested. The sensitivity, specificity and accuracy of the RAPINA test compared with rapid fluorescent focus inhibition test (RFFIT) as a standard test, were 88.7, 91.9 and 90.4%, respectively. The RAPINA test is a simple, safe and rapid method, which can be a substitute for neutralizing tests that use live viruses, cultured cells and fluorescence microscopy. This test might be useful for screening a large number of sera.     

Evaluation of a rapid test for detection of antibodies against human immunodeficiency virus (HIV)

A new test for rapid detection of HIV antibodies (HIVCHEK) was evaluated. A total of 107 sera were examined. Of these, 60 were from healthy blood donors and the rest from a serum panel containing HIV positives and samples with false positive reactions in ELISA and unspecific bands in the western blot (WB). There was close agreement (100%) between the methods. The specificity of the HIVCHEK was 100% in this study. The sensitivity was acceptably high based on testing of consecutive serum samples from two seroconversion patients. The test was rapid and easy to perform, and no extra equipment was needed.     

Development and evaluation of a rapid latex agglutination test using a monoclonal antibody to identify Candida dubliniensis colonies

Cell components of the dimorphic pathogenic fungus Candida dubliniensis were used to prepare monoclonal antibodies (MAbs). One MAb, designated 12F7-F2, was shown by indirect immunofluorescence to be specific for a surface antigen of Candida dubliniensis yeast cells. No reactivity was observed with other fungal genera or with other Candida species, including Candida albicans, that share many phenotypic features with C. dubliniensis. The use of different chemical and physical treatments for cell component extraction suggested that the specific epitope probably resides on a protein moiety absent from C. albicans. However, we failed to identify the target protein by Western blotting, owing to its sensitivity to heat and sodium dodecyl sulfate. MAb 12F7-F2 was further used to develop a commercial latex agglutination test to identify C. dubliniensis colonies (Bichro-dubli Fumouze test; Fumouze Diagnostics). The test was validated on yeast strains previously identified by PCR and on fresh clinical isolates; these included 46 C. dubliniensis isolates, 45 C. albicans isolates, and other yeast species. The test had 100% sensitivity and specificity for C. dubliniensis isolated on Sabouraud dextrose, CHROMagar Candida, and CandiSelect media and 97.8% sensitivity for C. dubliniensis grown on Candida ID medium. The test is rapid (5 min) and easy to use and may be recommended for routine use in clinical microbiology laboratories and for epidemiological investigations.     

Evaluation of Pyloriset Dry, a new rapid agglutination test for Helicobacter pylori antibody detection.

We evaluated the performance of a new latex agglutination test, Pyloriset Dry (Orion Diagnostica, Espoo, Finland), in the simultaneous detection of immunoglobulin G (IgG), IgA, and IgM antibodies to Helicobacter pylori and compared it with that of the Pyloristat test (BioWhittaker, Fontenay-sous-Bois, France), an enzyme-linked immunosorbent assay detecting IgG to H. pylori, for 96 untreated dyspeptic patients who had undergone gastroduodenal endoscopy. Infection was diagnosed in 56 cases by positive culture and/or positive Giemsa stain and rapid urease test (antral biopsies) and was associated with chronic gastritis in 52 patients. Forty noninfected patients did not have chronic gastritis. The sensitivity of Pyloriset Dry was 91.1%. The sensitivity of Pyloristat was 91.1 or 82.1%, depending on whether equivocal results were considered positive or negative, respectively. Both tests had a specificity of 87.5%. Their performances were not statistically different. Thus, Pyloriset Dry is an alternative to serological tests for adults, particularly when a small number of serum samples has to be tested.     

A simple and rapid immunochromatographic strip test for detecting antibody to porcine reproductive and respiratory syndrome virus

Porcine reproductive and respiratory syndrome is rapidly gaining worldwide importance as one of the most economically significant diseases of swine. The antibody of Porcine reproductive and respiratory syndrome virus (PRRSV) is detected currently by the combined use of an enzyme-linked immunosorbent assay, serum neutralization test, immunoperoxidase monolayer assay, indirect immunofluorescent antibody test. These methods are time-consuming and require specialized equipment operated by trained technicians. The purpose of this study was to evaluate a simple strip assay (based on a chromatographic and immunogold system) for specific detection of PRRSV antibody in swine sera. This "immunochromatographic strip" test uses Escherichia coli-expressed viral recombinant membrane protein antigen in combination with recombinant nucleocapsid protein as capture protein for detecting antibodies against PRRSV. In this study, the performance of this assay was evaluated with sera from both clinical samples and experimentally infected piglets. Detection by immunochromatographic strip test was compared with detection by a standard, available commercially, indirect enzyme-linked immunosorbent assay and an immunoperoxidase monolayer assay. The immunochromatographic test strip detected antibodies in sera known to contain antibodies to PRRSV in 95.7% sensitivity of samples from pigs infected experimentally and 98.6% sensitivity of clinical serum samples. For sera that did not contain antibodies to PRRSV, the specificity was 97.8% and 98.2% for clinical and experimental serum samples, respectively.