Conventional Enzyme Immunoassay Research Articles

Screening Cutoff Values for the Detection of Aldosterone-Producing Adenoma by LC-MS/MS and a Novel Noncompetitive CLEIA.

Detecting patients with surgically curable aldosterone-producing adenoma (APA) among hypertensive individuals is clinically pivotal. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is the ideal method of measuring plasma aldosterone concentration (PAC) because of the inaccuracy of conventional chemiluminescent enzyme immunoassay (CLEIA). However, LC-MS/MS is expensive and requires expertise. We have developed a novel noncompetitive CLEIA (NC-CLEIA) for measuring PAC in 30 minutes. This work aimed to validate NC-CLEIA PAC measurements by comparing them with LC-MS/MS measurements and determining screening cutoffs for both measurements detecting APA. We retrospectively measured PAC using LC-MS/MS and NC-CLEIA in 133 patients with APA, 100 with bilateral hyperaldosteronism, and 111 with essential hypertension to explore the accuracy of NC-CLEIA PAC measurements by comparing with LC-MS/MS measurements and determined the cutoffs for detecting APA. Passing-Bablok analysis revealed that the values by NC-CLEIA (the regression slope, intercept, and correlation coefficient were 0.962, -0.043, and 0.994, respectively) were significantly correlated and equivalent to those by LC-MS/MS. Bland-Altman plot analysis of NC-CLEIA and LC-MS/MS also demonstrated smaller systemic errors (a bias of -0.348 ng/dL with limits of agreement of -4.390 and 3.694 within a 95% CI) in NC-CLEIA than LC-MS/MS. The receiver operating characteristic analysis demonstrated that cutoff values for aldosterone/renin activity ratio obtained by LC-MS/MS and NC-CLEIA were 31.2 and 31.5 (ng/dL per ng/mL/hour), with a sensitivity of 91.0% and 90.2% and specificity of 75.4% and 76.8%, respectively, to differentiate APA from non-APA. This newly developed NC-CLEIA for measuring PAC could serve as a clinically reliable alternative to LC-MS/MS.

Pandemic influenza A(H1N1pdm09) vaccine induced high levels of influenza-specific IgG and IgM antibodies as analyzed by enzyme immunoassay and dual-mode multiplex microarray immunoassay methods

Influenza A viruses continue to circulate throughout the world as yearly epidemics or occasional pandemics. Influenza infections can be prevented by seasonal multivalent or monovalent pandemic vaccines. In the present study, we describe a novel multiplex microarray immunoassay (MAIA) for simultaneous measurement of virus-specific IgG and IgM antibodies using Pandemrix-vaccinated adult sera collected at day 0 and 28 and 180 days after vaccination as the study material. MAIA showed excellent correlation with a conventional enzyme immunoassay (EIA) in both IgG and IgM anti-influenza A antibodies and good correlation with hemagglutination inhibition (HI) test. Pandemrix vaccine induced 5–30 fold increases in anti-H1N1pdm09 influenza antibodies as measured by HI, EIA or MAIA. A clear increase in virus-specific IgG antibodies was found in 93–97% of vaccinees by MAIA and EIA. Virus-specific IgM antibodies were found in 90–92% of vaccinees by MAIA and EIA, respectively and IgM antibodies persisted for up to 6 months after vaccination in 55–62% of the vaccinees. Pandemic influenza vaccine induced strong anti-influenza A IgG and IgM responses that persisted several months after vaccination. MAIA was demonstrated to be an excellent method for simultaneous measurement of antiviral IgG and IgM antibodies against multiple virus antigens. Thus the method is well suitable for large scale epidemiological and vaccine immunity studies.

The Neuroendocrine and Metabolic Outcomes of Bariatric Surgery Depend on Presurgical Control over Eating

Background: The outcomes of bariatric surgery are very irregular and mostly unpredictable. The search for variables of predictive value is encouraged to help preventing therapeutic failures. Objective: We aimed to confirm the hypothesis that preexisting eating behaviors could predict neuroendocrine and metabolic outcomes of gastric bypass surgery in morbidly obese subjects. Methods: Twenty-one morbidly obese patients from the Bariatric Surgery Program of our hospital were selected according to the specific inclusion and exclusion criteria for this study. The subjects filled out a validated questionnaire to quantify the “loss-of-control” (LC) dimension of food craving and provided serum samples at the onset of the study and 1 year after gastric bypass surgery. Hematological, metabolic, and hormonal variables were studied by conventional clinical tests and enzyme immunoassays and checked for correlations with LC both before and after surgery. Results: Those patients that had exhibited worse eating control at the beginning of the study experienced a better metabolic response 1 year after surgery in terms of reduction of serum insulin, HOMA1-IR, HOMA2-IR, and vitamin D₁; all these variables were inversely correlated with presurgical LC. Serum brain-derived neurotrophic factor (BDNF) levels showed the same tendency; in fact, BDNF significantly decreased only in those patients with worse eating control. Conclusions: Problematic eating behaviors may predict a better response of insulin resistance and a specific reduction of serum BDNF in morbidly obese patients after gastric bypass surgery.

The immune complex transfer enzyme immunoassay: Mechanism of improved sensitivity compared with conventional sandwich enzyme immunoassay

Immune complex transfer enzyme immunoassay (ICT-EIA) is one of the technologies which enables ultrasensitive measurements of protein biomarkers. The ICT-EIA uses two types of beads and sandwich-shaped immune complexes are transferred from the 1st bead to the 2nd bead in the assay. The purpose of the study is to reveal the reason why the ICT-EIA achieves ultrasensitive measurements by making a detailed comparison between conventional sandwich enzyme immunoassay (Sand-EIA) and ICT-EIA. ICT-EIAs for cytokines were developed and the sensitivities were compared with the sandwich EIAs. ICT-EIAs had about 100 times higher sensitivities because of markedly decreased non-specific signals derived from non-specific binding of detection antibody conjugates onto the polystyrene bead. The results have enabled us to show the importance of reducing non-specific signals in EIAs to obtain higher sensitivities. This methodology should be more valuable if combined with a different label detection system such as digital counting or immuno-PCR, which may enable the detection of single target protein molecules in the near future.

Impact of simultaneous glutamate dehydrogenase and toxin A/B rapid immunoassay on Clostridium difficile diagnosis and treatment in hospitalized patients with antibiotic-associated diarrhea in a university hospital of Brazil.

Clostridium difficile is a major cause of health care-associated infection, but disagreement between diagnostic tests is an ongoing barrier to clinical decision-making. Conventional enzyme immunoassay (EIA) for toxin detection is currently the most frequently used technique for C.difficile infection (CDI) diagnosis, but its low sensitivity makes the development of an alternative strategy necessary for improving the diagnosis in developing countries. Between years 2011 and 2015, 154 stool samples from patients with antibiotic-associated diarrhea were examined by toxigenic culture and EIA for the diagnosis of CDI. In the year 2015, when glutamate dehydrogenase (GDH) test was first available in Brazil, 53 of those fecal specimens were also tested by the C. diff Quik Chek Complete rapid immunoassay. At this time, we prospectively assessed the impact of this test on CDI treatment rates before and after it was introduced in clinical practice. The GDH component of C. diff Quik Chek Complete test had a sensitivity of 100% and specificity of 95.1% compared with toxigenic culture, with 89.8% concordance. The Tox A/B II EIA and the toxin portion of C. diff Quik Chek Complete yielded sensitivities between values of 50-58.3%, with 100% specificities. The introduction of GDH test increased the number of treated patients with CDI from 57.7% to 100%. Glutamate dehydrogenase test is a reliable method for the diagnosis of CDI and greatly increases the number of properly treated patients with CDI. Therefore, this exam should be considered the mainstay for the laboratory diagnosis of CDI in developing countries.

Implementing Expanded Rapid Human Immunodeficiency Virus Testing in Public Health Centers in Seoul, 2015

In 2015, rapid human immunodeficiency virus (HIV) testing was implemented in all 25 public health centers in Seoul. During March and December 2015, 20,987 rapid HIV tests were performed, of which 116 (0.5%) were positive. Compared to those of the period before application of the rapid HIV test in place of conventional enzyme immunoassay method, the number of HIV tests performed and the number of positive results increased by sevenfold and twofold, respectively. In conclusion, expansion of the provision of rapid HIV tests in public health centers increased the number of voluntary HIV tests.

Screening for Human Immunodeficiency Virus, Hepatitis B Virus, Hepatitis C Virus, and Treponema pallidum by Blood Testing Using a Bio-Flash Technology-Based Algorithm before Gastrointestinal Endoscopy.

Currently, conventional enzyme immunoassays which use manual gold immunoassays and colloidal tests (GICTs) are used as screening tools to detect Treponema pallidum (syphilis), hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus type 1 (HIV-1), and HIV-2 in patients undergoing surgery. The present observational, cross-sectional study compared the sensitivity, specificity, and work flow characteristics of the conventional algorithm with manual GICTs with those of a newly proposed algorithm that uses the automated Bio-Flash technology as a screening tool in patients undergoing gastrointestinal (GI) endoscopy. A total of 956 patients were examined for the presence of serological markers of infection with HIV-1/2, HCV, HBV, and T. pallidum. The proposed algorithm with the Bio-Flash technology was superior for the detection of all markers (100.0% sensitivity and specificity for detection of anti-HIV and anti-HCV antibodies, HBV surface antigen [HBsAg], and T. pallidum) compared with the conventional algorithm based on the manual method (80.0% sensitivity and 98.6% specificity for the detection of anti-HIV, 75.0% sensitivity for the detection of anti-HCV, 94.7% sensitivity for the detection of HBsAg, and 100% specificity for the detection of anti-HCV and HBsAg) in these patients. The automated Bio-Flash technology-based screening algorithm also reduced the operation time by 85.0% (205 min) per day, saving up to 24 h/week. In conclusion, the use of the newly proposed screening algorithm based on the automated Bio-Flash technology can provide an advantage over the use of conventional algorithms based on manual methods for screening for HIV, HBV, HCV, and syphilis before GI endoscopy.

Comparison between the accuracy of a rapid point-of-care HIV test TOYO versus ELISA, Western Blot, and RT-PCR analysis

Background: The human immunodeficiency virus (HIV) is considered one of the most serious health challenges worldwide. Early detection and diagnosis are key elements in the effort to control HIV. Rapid tests for the detection of HIV-antibody allow timely point-of-care provision of results and do not require the laboratory facilities needed for conventional enzyme immunoassays (enzyme-linked immunosorbent assay [ELISA]) and Western blot (WB) testing. Regardless of the advantages of these tests, other studies showed that the sensitivity of the performance of some rapid test brands comparing with the lab standard methods have some limitation. Objective: This study evaluated and compared the performance of commercially available HIV rapid test TOYO against the gold standard tests used in the clinical laboratories at Saudi Arabia. Materials and Methods: Forty-two male and female patient samples were tested with real-time polymerase chain reaction (RT-PCR), ELISA, and/or WB followed by TOYO rapid test to compare their results when performed under similar conditions. Results: The higher compatibility of TOYO results was observed with RT-PCR with 81% followed by WB and ELISA with 76% and 63%, respectively. However, more than 25% of the results showed either false positive or false negative results when compared with either of the standard diagnostic tests used in this study. Conclusion: This study have provided evidence that TOYO rapid HIV assay cannot perform equally as RT-PCR, ELISA, or WB for the detection of HIV antibodies. A further study is suggested to compare the performance of TOYO rapid test against standard diagnostic tests with larger number of patients’ samples.

Validation study of a conventional enzyme immunoassay to detect HIV antibodies in oral fluid

The aim of our study was to validate the Genscreen HIV ½ version 2 (BIO-RAD) for detecting HIV antibodies in oral fluid specimens (OF). The advantage of assays to detect HIV infection in OF lies in the on-site easy access and noninvasive sample collection. Paired serum and OF were collected from 496 subjects (263 HIV-positive and 233 HIV-negative) using the Oracol test kit (Oracle Diagnostics, Inc). The quality of OF was verified by measuring total IgGs using the Human IgG ELISA Quantitation Kit (Bethyl Lab.inc). All reactive OF samples were retested by Western blot HIV1/2 BLOT 2.2 (MP Biomedical, Singapore, China). Of 263 OF samples from participants with blood-based HIV-positive results, 259 were positive by Genscreen HIV ½ version 2 (98.48% sensitivity, 95% CI; 96.2-99.6). The 233 individuals who had a non-reactive HIV blood test were found negative on testing their OF by Genscreen HIV ½ version 2 (100% specificity, 95% CI; 98.4-100). NPV and PPV of the assay were 98.31% (95% CI; 95.74-99.34) and 100%, (95% CI; 98.53-100.00), respectively. Genscreen HIV ½ version 2 (Bio-Rad) is aprospective method for HIV surveillance studies in hard-to-reach populations with high risk behavior using non-invasive OF collection (Tab. 1, Fig. 1, Ref. 16).

Performance of a new rapid test for detecting anti-hepatitis E virus immunoglobulin M in immunocompetent and immunocompromised patients

BackgroundHepatitis E virus (HEV) infections are widespread in both developing and developed countries. It is, therefore, important to assess the performance of systems for rapidly detecting anti-HEV immunoglobulin M antibodies in human sera. ObjectivesTo evaluate the diagnostic value of a new immunochromatographic assay, the HEV IgM rapid test (Wantai). Study designBlood samples were taken from 30 acutely infected immunocompetent and 30 acutely infected immunocompromised patients, all with HEV RNA in their blood. Specificity and cross reactivity was assessed using samples from 30HEV RNA negative immunocompetent patients who had acute Epstein–Barr virus (EBV) or cytomegalovirus (CMV) infections and 30HEV RNA negative immunocompromised patients. The performance of the HEV IgM Rapid Test was compared to that of a conventional microplate enzyme immunoassay. ResultsThe sensitivity of the rapid test in immunocompetent patients was 90% (95% CI: 72.1–100%), similar to that of the Wantai microplate assay (sensitivity: 96.6%, 95% CI: 78.77–100%; p=0.61). The sensitivity of the rapid test in immunocompromised patients was 73.3% (95% CI: 55.4–91.2%) and that of the microplate assay was 83.3% (95% CI: 65.44–100%; p=0.53). The rapid test produced no false positive reactions with samples from HEV RNA negative patients; while the microplate assay gave two false positive results (3.3%). ConclusionThe new Wantai HEV IgM rapid test is easy to use and suitable for rapidly detecting acute hepatitis E infections in both immunocompetent and immunocompromised patients. However, HEV RNA must be detected using a molecular assay for diagnosing an HEV infection in anti-HEV IgM negative patients.

Towards pain-free diagnosis of skin diseases through multiplexed microneedles: biomarker extraction and detection using a highly sensitive blotting method.

Immunodiagnostic microneedles provide a novel way to extract protein biomarkers from the skin in a minimally invasive manner for analysis in vitro. The technology could overcome challenges in biomarker analysis specifically in solid tissue, which currently often involves invasive biopsies. This study describes the development of a multiplex immunodiagnostic device incorporating mechanisms to detect multiple antigens simultaneously, as well as internal assay controls for result validation. A novel detection method is also proposed. It enables signal detection specifically at microneedle tips and therefore may aid the construction of depth profiles of skin biomarkers. The detection method can be coupled with computerised densitometry for signal quantitation. The antigen specificity, sensitivity and functional stability of the device were assessed against a number of model biomarkers. Detection and analysis of endogenous antigens (interleukins 1α and 6) from the skin using the device was demonstrated. The results were verified using conventional enzyme-linked immunosorbent assays. The detection limit of the microneedle device, at ≤10pg/mL, was at least comparable to conventional plate-based solid-phase enzyme immunoassays.

Outcomes of Infants Born to HIV-Infected Women Identified by Rapid HIV Testing Late in Pregnancy or at Delivery: The MIRIAD Study

Background: Rapid HIV testing late in pregnancy or at delivery provides a final opportunity (among non-breastfeeding mothers) to identify HIV-infected women and initiate antiretroviral drugs to prevent mother-to-child transmission. Methods: MIRIAD was a CDC-funded study conducted from 2001-2005 at 17 hospitals in 6 US cities. Eligible women had undocumented HIV status when presenting in labor or after 34 weeks gestation and not in labor. We performed both rapid HIV-1 antibody testing of blood and conventional enzyme immunoassay with Western blot confirmation. Women and infants were managed according to the local standard of care. Infant infection status was determined by HIV DNA or RNA PCR testing. Results: Fifty-one infants (1 pair of twins) were born to 50 women. Among those with data available, 17% of women received prenatal antiretroviral and 71% received intrapartum antiretroviral, including 64% of those identified during labor. All 49 infants with available data received antiretroviral. Forty-four infants had adequate samples to determine their infection status and 5 were infected (11.4%, 95% CI: 1.9 - 20.7%); 3 had in utero, 1 intrapartum, and 1 indeterminate timing of transmission. No infant whose mother received prenatal antiretroviral was infected. The estimated rate of intrapartum transmission among infants with defined infection status was 4.5%. Conclusions: Rapid HIV testing late in pregnancy or even during labor, allowing the administration of antiretroviral to infected women, reduces intrapartum HIV transmission. This highlights the importance of offering rapid HIV testing to pregnant women, with unknown HIV status late in pregnancy.

Accurate detection of Campylobacter spp. antigens by immunochromatography and enzyme immunoassay in routine microbiological laboratory.

Campylobacter spp. are fastidious microorganisms, and their detection by culture depends on the freshness of the stool sample and the skills of the laboratory staff. To improve laboratory diagnosis, assays for the detection of specific antigens have been developed. Here, we evaluated two assays for the detection of Campylobacter spp.-specific antigens, i.e., one immunochromatographic test and one enzyme-linked immunosorbent assay (EIA), in 38 frozen Campylobacter spp.-positive specimens and prospectively in 533 fresh stool samples with a conventional enzyme immunoassay (EIA) and culture. Both assays were positive for 36 samples with Campylobacter jejuni and one with Campylobacter coli among 38 Campylobacter spp.-positive frozen samples. One Campylobacter lari-positive sample was identified by the immunochromatographic assay (ICA) only. In a prospective study performed within the course of routine microbiology, both assays were positive for 24/25 C. jejuni culture-positive samples (positive percent agreement, 96.0% [95% CI: 78.9-100%]). ICA and EIA also were positive for 14 and 10 culture-negative samples, respectively (negative percent agreement: ICA, 97.2% [95% CI: 95.4-98.4%]; EIA, 98.0% [95% CI: 96.4-99.0%]). In conclusion, the high agreement between both antigen-detection assays and culture indicates that both assays may be initially performed followed by culture only upon a positive test result.

Rapid aptasensor capable of simply diagnosing prostate cancer

Using guanine (G)-rich DNA aptamer-conjugated 6-carboxyfluorescein (6-FAM) capable of rapidly capturing prostate specific antigen (PSA) in human serum, cost-effective and simple biosensor with guanine chemiluminescence detection was developed for early diagnosis of prostate cancer. Free G-rich DNA aptamer-conjugated 6-FAM emits bright light in guanine chemiluminescence reaction based on the principle of chemiluminescent resonance energy transfer (CRET). However, G-rich DNA aptamer-conjugated 6-FAM bound with PSA cannot emit light because PSA acts as a strong interference in CRET between 6-FAM and high-energy intermediate formed from the reaction of 3,4,5-trimethoxylphenylglyoxal (TMPG) and guanine of G-rich DNA aptamer. A chemiluminescent biosensor, developed using the different properties of G-rich DNA aptamer-conjugated 6-FAM in the absence and presence of PSA in guanine chemiluminescence reaction, was able to quantify trace levels of PSA in human serum within 30min without time-consuming and complicated procedures (e.g., multiple incubation and washings) required for conventional immunoassays operated with expensive and intractable antibodies. The limit of detection of chemiluminescent biosensor having a wide linear dynamic range (1.9–125ng/ml) was 1.0ng/ml. The excellent correlation (R=0.985) between chemiluminescent biosensor and conventional enzyme immunoassay indicates that the accurate, precise, and rapid chemiluminescent biosensor can be applied as a new method for early diagnosis of prostate cancer.

Novel microarrays for simultaneous serodiagnosis of multiple antiviral antibodies.

We developed an automated diagnostic system for the detection of virus-specific immunoglobulin Gs (IgGs) that was based on a microarray platform. We compared efficacies of our automated system with conventional enzyme immunoassays (EIAs). Viruses were immobilized to microarrays using a radical cross-linking reaction that was induced by photo-irradiation. A new photoreactive polymer containing perfluorophenyl azide (PFPA) and poly(ethylene glycol) methacrylate was prepared and coated on plates. Inactivated measles, rubella, mumps, Varicella-Zoster and recombinant Epstein-Barr viruse antigen were added to coated plates, and irradiated with ultraviolet light to facilitate immobilization. Virus-specific IgGs in healthy human sera were assayed using these prepared microarrays and the results obtained compared with those from conventional EIAs. We observed high correlation (0.79–0.96) in the results between the automated microarray technique and EIAs. The microarray-based assay was more rapid, involved less reagents and sample, and was easier to conduct compared with conventional EIA techniques. The automated microarray system was further improved by introducing reagent storage reservoirs inside the chamber, thereby conserving the use of expensive reagents and antibodies. We considered the microarray format to be suitable for rapid and multiple serological diagnoses of viral diseases that could be developed further for clinical applications.

Diagnostic value of a “wide‐range” quantitative nested real‐time PCR assay for varicella zoster virus myelitis

Myelitis is one of the rarest neurological complications of varicella zoster virus (VZV) infection. In this study, the authors remodeled the "wide-range" quantitative nested real-time (QNRT) polymerase chain reaction (PCR) assay to quantitatively detect a small amount of VZV-DNA in cerebrospinal fluid (CSF). For use as a specific internal control "calibrator," an original mutation-VZV (MZ) plasmid was developed. The initial copy number of VZV-DNA in CSF specimens was measured by the amplification rate of the MZ-plasmid. For 17 consecutive CSF specimens collected from three elderly patients with VZV myelitis, the diagnostic value of the wide-range QNRT-PCR assay was evaluated and compared with other conventional PCR assays and enzyme immunoassay (EIA). The MZ-plasmid demonstrated statistically uniform amplifications (F=1.016) against a wide range (1-100,000) of copy numbers of mimic VZV-DNA. The wide-range QNRT-PCR assay quantitatively and rapidly (within 48 hr) detected 5,863, 3,052, 958, and 6,721 copies/ml of VZV-DNA in the CSF specimens collected from all patients in the acute phase. Additionally, there was a significant difference (*P=0.023) in the copy number of VZV-DNA between before and after acyclovir treatment. Other conventional single PCR assays all revealed negative results, but were nevertheless time-consuming (7 days). The IgG EIA-value for VZV was continually elevated throughout the clinical course of all patients. The MZ-plasmid was thus regarded as an appropriate "calibrator" in the wide-range QNRT-PCR assay. This assay is a novel, rapid, accurate, quantitative, and highly sensitive technique, and will contribute as a reliable and useful clinical examination for the rapid diagnosis of VZV infection to central nervous system.

Surface-activated microtiter-plate microarray for simultaneous CRP quantification and viral antibody detection

Microarrays are widely used in high-throughput DNA and RNA hybridization tests and recently adopted to protein and small molecule interaction studies in basic research and diagnostics. Parallel detection of serum antibodies and antigens has several potential applications in epidemiologic research, vaccine development, and in the diagnosis of allergies, autoimmunity, and infectious diseases. This study demonstrates an immobilization method for immunoassay-based microarray in conventional 96-well polystyrene plates for a serologic diagnostic method combined with quantitative C-reactive protein (CRP) assay. A synthetic peptide (HIV-1), a recombinant protein (Puumala hantavirus nucleocapsid), and purified virus preparations (Sindbis and adenoviruses) were used as antigens for virus-specific antibody detection and monoclonal anti-CRP antibody for antigen detection. The microarray was based on conventional enzyme immunoassays and densitometry from photographed results. Peptide and recombinant antigens functioned well, while whole virus antigens gave discrepant results in 1 out of 23 samples from the reference method, tested with human sera with various antibody responses. The CRP results were in concordance in the concentration range 0.5–150 mg/L with 2 commercially available CRP assays: ReaScan rapid test (R2 = 0.9975) and Cobas 6000 analyzer (R2 =0.9595). The results indicate that microtiter plates provide a promising platform for further development of microarrays for parallel antibody and antigen detection.

Clinical impact of switching conventional enzyme immunoassay with nucleic acid amplification test for suspected Clostridium difficile-associated diarrhea

The impact of a new Clostridium difficile nucleic acid amplification test (NAAT) on antibiotic utilization in patients with suspected C difficile infection was assessed. This single-center, cross-sectional study of 270 patients demonstrated that the use of NAAT decreased antibiotic expenditure by reducing prolonged empiric days of therapy in these patients.

Evaluation of accuracy of OraQuick® rapid test in detecting HIV antibodies in saliva of Nigerians

Objective: The accuracy of OraQuick® rapid test in detecting HIV 1 & 2 antibodies in saliva is evaluated against the blood EIA benchmark tests with confirmatory testing, against which OraQuick® accuracy is determined.Method: Paired samples of saliva and blood from 281 Nigerians were tested for HIV antibodies, and compared for sensitivity and specificity. Subjects included in the study were those who had a complete test, which included saliva test with OraQuick® rapid test, serologic test using conventional Enzyme Immunoassay (EIA), and confirmatory serological test.Result: From the 281 subjects who completed the oral fluid-based OraQuick® tests & EIA with confirmatory tests, 192 were seropositive and 89 seronegative for HIV 1 & 2 antibodies. The sensitivity (95% CI) of OraQuick® was 98.96% (97.98% to 99.96%) and specificity was 100% thereby comparing favorably with serum EIA with benchmark sensitivity of 100% and specificity (95% CI) of 96.63% (95.61 to 97.56).Conclusion: Saliva based OraQuick® rapid assays for detecting HIV antibodies using oral fluids give accurate sensitivity and specificity results comparable to EIA results with serum samples. They are more acceptable, easier to use and not invasive.

Evaluation of accuracy of OraQuick® rapid test in detecting HIV antibodies in saliva of Nigerians

Objective: The accuracy of OraQuick ® rapid test in detecting HIV 1 & 2 antibodies in saliva is evaluated against the blood EIA benchmark tests with confirmatory testing, against which OraQuick ® accuracy is determined. Method : Paired samples of saliva and blood from 281 Nigerians were tested for HIV antibodies, and compared for sensitivity and specificity. Subjects included in the study were those who had a complete test, which included saliva test with OraQuick ® rapid test, serologic test using conventional Enzyme Immunoassay (EIA), and confirmatory serological test. Result : From the 281 subjects who completed the oral fluid-based OraQuick ® tests & EIA with confirmatory tests, 192 were seropositive and 89 seronegative for HIV 1 & 2 antibodies. The sensitivity (95% CI) of OraQuick ® was 98.96% (97.98% to 99.96%) and specificity was 100% thereby comparing favorably with serum EIA with benchmark sensitivity of 100% and specificity (95% CI) of 96.63% (95.61 to 97.56). Conclusion : Saliva based OraQuick ® rapid assays for detecting HIV antibodies using oral fluids give accurate sensitivity and specificity results comparable to EIA results with serum samples. They are more acceptable, easier to use and not invasive. Key words : Oraquick, saliva, HIV detection