Antibody Enzyme Immunoassay Research Articles

Histoplasmosis in domestic cats: new minimally invasive diagnostic techniques.

The aim of the present study was to evaluate minimally invasive diagnostic techniques, such as the semi-quantitative indirect IgG antibody enzyme immunoassay (EIA) using blood serum and the urinary lateral flow assay (LFA), for the detection of Histoplasma capsulatum in cats with histoplasmosis. Eight client-owned domestic cats diagnosed with histoplasmosis were selected based on cytological, histopathological, mycological, molecular or antigenic techniques. The blood serum of these animals was tested in a semi-quantitative indirect IgG antibody EIA for the detection of H capsulatum. Urine samples were tested for H capsulatum antigen using LFA. Five cats were seropositive on IgG EIA (5/8, with diagnostic sensitivity equal to 62.5%; 95% confidence interval [CI] 24.5-91.5) and five cats were positive on H capsulatum antigen LFA (5/7, with diagnostic sensitivity equal to 71.4%; 95% CI 29.0-96.3). The combined diagnostic sensitivity when interpreted in parallel was 87.5% (7/8, 95% CI 47.3-99.7). The specificity for the anti-Histoplasma IgG EIA was 100% (95% CI 71.5-100) and for the H capsulatum antigen LFA it was also 100% (95% CI 71.5-100). The semi-quantitative indirect IgG antibody EIA for the detection of H capsulatum in blood serum and the urinary LFA for the detection of the same agent emerge as new minimally invasive diagnostic techniques that can assist in the approach to disseminated and pulmonary feline histoplasmosis, especially when both techniques are considered together.

Seroprevalence of Measles (Rubeola) Antibodies in Childhood Cancer Survivors.

Background: Measles is reemerging as a public health threat, raising important questions about disease vulnerability among childhood cancer survivors. This secondary analysis assessed the seroprevalence of anti-measles immunoglobulin G (IgG) antibodies as a marker of immune status in survivors of childhood cancer and associated demographic/treatment variables. Method: Participants were childhood cancer survivors who were free of active disease, having routine blood studies drawn, and could provide documentation of having received two doses of measles, mumps, and rubella vaccine before their cancer diagnosis. Patient record review documented demographic and treatment variables. Antimeasles (rubeola) IgG antibody seroprevalence was assessed by enzyme immunoassay for vaccine-specific antibodies. Results: Of 270 survivors evaluated, 110 (42%) were female, 196 (75%) were White, and 159 (61%) were leukemia/lymphoma survivors. Of these 262, 110 (42%) had negative measles seroprevalence, suggesting loss of immunity. Conclusion: Measles antibody surveillance and the need for reimmunization for survivors of childhood cancer survivors outside the transplant setting remains controversial. Our analysis indicates that a substantial proportion of survivors lose vaccine-related immunity to measles. Pediatric oncology nurses play important roles in educating cancer survivors regarding their risk of measles infection, evaluating the need for reimmunization, correcting misinformation about vaccine safety and effectiveness, and working to optimize community herd-based immunity.

Development and comparison of immunologic assays to detect primary RSV infections in infants.

Effective respiratory syncytial virus (RSV) vaccines have been developed and licensed for elderly adults and pregnant women but not yet for infants and young children. The RSV immune state of the young child, i.e., previously RSV infected or not, is important to the conduct and interpretation of epidemiology studies and vaccine clinical trials. To address the need for sensitive assays to detect immunologic evidence of past infection, we developed, characterized, and evaluated 7 assays including 4 IgG antibody enzyme immunoassays (EIAs), two neutralizing antibody assays, and an IFN-γ EliSpot (EliSpot) assay. The four IgG EIAs used a subgroup A plus subgroup B RSV-infected Hep-2 cell lysate antigen (Lysate), an expressed RSV F protein antigen (F), an expressed subgroup A G protein antigen (Ga), or an expressed subgroup B G protein (Gb) antigen. The two neutralizing antibody assays used either a subgroup A or a subgroup B RSV strain. The EliSpot assay used a sucrose cushion purified combination of subgroup A and subgroup B infected cell lysate. All seven assays had acceptable repeatability, signal against control antigen, lower limit of detection, and, for the antibody assays, effect of red cell lysis, lipemia and anticoagulation of sample on results. In 44 sera collected from children >6 months after an RSV positive illness, the lysate, F, Ga and Gb IgG EIAs, and the subgroup A and B neutralizing antibody assays, and the EliSpot assays were positive in 100%, 100%, 86%, 95%, 43%, and 57%, respectively. The Lysate and F EIAs were most sensitive for detecting RSV antibody in young children with a documented RSV infection. Unexpectedly, the EliSpot assay was positive in 9/15 (60%) of PBMC specimens from infants not exposed to an RSV season, possibly from maternal microchimerism. The Lysate and F EIAs provide good options to reliably detect RSV antibodies in young children for epidemiologic studies and vaccine trials.

Assessment of the reliability of serological monitoring results based on biobank materials

Aim. To evaluate the safety of immunoglobulins (Ig) of different classes (IgA, IgM, IgG, IgE) under conditions of long-term low-temperature storage of blood serum samples.Material and methods. The work used samples of blood serum from the collection of the Department of Epidemiology, examined by enzyme immunoassay for antibodies of classes IgA, IgM, IgG, IgE twice as follows: immediately upon receipt in the laboratory and after storage at a temperature of -70о C for 8 years.Results. After the storage of seropositive sera, the level of IgA antibodies did not change significantly (p=0,7). For the remaining classes of immunoglobulins (IgM, IgG, IgE), a small (not >15%) but significant decrease (p<0,05), most pronounced for IgE, was observed. It was shown that the higher the antibody level in the samples during the first study, the more it decreased after long-term storage (correlation at p<0,05). This did not lead to false negative results, which is due to the greater accuracy in measuring small values.Conclusion. Long-term low-temperature storage of serum samples in biobank conditions ensures the safety of antibodies of different classes and is the basis for the reliability of future studies.

Algorithm for monitoring patients after tick bite in the context of Lyme-borreliosis

Timely diagnosis of Lyme-borreliosis (LB) is the key to its successful treatment. Outpatient monitoring of patients after tick bite based on the algorithm is able to optimize the early diagnosis of LB, shorten the start of treatment and improve the disease surveillance.Purpose. Creation of an algorithm for monitoring patients after tick bite for use in outpatient settings by primary care physicians. Material and methods. A retrospective, non-randomized, single-center cohort study was conducted based on the analysis of data from 660 outpatient records of patients consulted by an infectious disease specialist in the Infectious clinical hospital No.1 in Moscow. Patients were divided by age and the presence or absence of a diagnosis of LB. Confirmation of the diagnosis was carried out according to clinical and/or laboratory criteria using methods of enzyme-linked immunoassay and immune blot. Results. The analysis of the results of enzyme immunoassay of antibodies to borrelia in patients with LB was carried out. The optimal sampling time was 7 or more weeks from the moment of tick bite and 4 or more weeks from the moment of onset of symptoms. The specificity of immunological diagnostics in patients with excluded LB was evaluated. The proportion of doubtful and false positive results in such patients was high — 28.1%. False positive results were more common in adults (37.6%) compared with children (9.8%), which is associated with more frequent false positive results of IgM determination (34.1% in adults, 4.9% in children). Based on the data of our study, an algorithm for monitoring patients after tick bite has been developed, focused on use in outpatient settings by primary care physicians.

Sampling algorithm for geno- and subtyping of hepatitis B virus using panel of monoclonal antibodies in enzyme immunoassay

Introduction. Previously, a domestic method for determining hepatitis B virus (HBV) genotypes and HBV surface antigen (HBsAg) subtypes in HBsAgpositive blood serum samples with a Monoclonal Antibody Panel (MAB) by enzyme immunoassay (ELISA) was described. In routine laboratory practice, HBsAg detection results are obtained in units of optical density (OD).Purpose. To describe the sampling algorithm for ELISA geno- and subtyping of HBV with the MAB Panel.Materials and methods. We studied 40 blood serum samples with positive results of HBsAg determination. HBV genotypes and HBsAg subtypes were determined using four different MAB conjugates with horseradish peroxidase using the ELISA method described previously.Results. In samples with OD less than 2.0 o. u. and confirmation of HBsAg after a single confirmatory study (n = 19) HBV genotypes/ HBsAg subtypes not established. In samples with an OD above 2.0 o. u. and verification of the presence of the antigen in the standard mode of registration (n = 15), immunoenzymatic geno- and subtyping of HBV was effective in 27 % of cases (4/15); for samples with HBsAg verification carried out in an auxiliary measurement (n = 6) the effectiveness of the technique was 100 %. Using the MAB panel in ELISA, the characteristics of HBV in 10 samples with the presence of HBsAg were studied: HBV genotype D (n = 10), subtypes ayw2 (n = 7), ayw3 (n = 3).Conclusions. For the most effective application of the HBV geno- and subtyping technique using the MAB Panel in ELISA, HBsAg+ samples with OD signals of more than 2.0 o. u. in screening and verification of the presence of an antigen in the auxiliary mode of registration of results should be used.

Human Intramuscular Hyperimmune Gamma Globulin (hIHGG) Anti-SARS-CoV-2-Characteristics of Intermediates and Final Product.

This study aims to characterize the intermediates, and the final product (FP) obtained during the production of human intramuscular hyperimmune gamma globulin anti-SARS-CoV-2 (hIHGG anti-SARS-CoV-2) and to determine its stability. Material and methods: hIHGG anti-SARS-CoV-2 was fractionated from 270 convalescent plasma donations with the Cohn method. Prior to fractionation, the plasma was inactivated (Theraflex MB Plasma). Samples were defined using enzyme immunoassays (EIA) for anti-S1, anti-RBD S1, and anti-N antibodies, and neutralization assays with SARS-CoV-2 (VN) and pseudoviruses (PVN, decorated with SARS-CoV-2 S protein). Results were expressed as a titer (EIA) or 50% of the neutralization titer (IC50) estimated in a four-parameter nonlinear regression model. Results: Concentration of anti-S1 antibodies in plasma was similar before and after inactivation. Following fractionation, the anti-S1, anti-RBD, and anti-N (total tests) titers in FP were concentrated approximately 15-fold from 1:4 to 1:63 (1800 BAU/mL), 7-fold from 1:111 to 1:802 and from 1:13 to 1:88, respectively. During production, the IgA (anti-S1) antibody titer was reduced to an undetectable level and the IgM (anti-RBD) titer from 1:115 to 1:24. The neutralizing antibodies (nAb) titer increased in both VN (from 1:40 to 1:160) and PVN (IC50 from 63 to 313). The concentration of specific IgG in the FP did not change significantly for 14 months. Conclusions: The hIHGG anti-SARS-CoV-2 was stable, with concentration up to approximately 15-fold nAb compared to the source plasma pool.

Optimizing use of multi-antibody assays for Lyme disease diagnosis: A bioinformatic approach.

Multiple different recombinant and peptide antigens are now available for serodiagnosis of Lyme disease (LD), but optimizing test utilization remains challenging. Since 1995 the Centers for Disease Control and Prevention (CDC) has recommended a 2-tiered serologic approach consisting of a first-tier whole-cell enzyme immunoassay (EIA) for polyvalent antibodies to Borrelia burgdorferi followed by confirmation of positive or equivocal results by IgG and IgM immunoblots [standard 2-tiered (STT) approach]. Newer modified 2-tiered (MTT) approaches employ a second-tier EIA to detect antibodies to B. burgdorferi rather than immunoblotting. We applied modern bioinformatic techniques to a large public database of recombinant and peptide antigen-based immunoassays to improve testing strategy. A retrospective CDC collection of 280 LD samples and 559 controls had been tested using the STT approach as well as kinetic-EIAs for VlsE1-IgG, C6-IgG, VlsE1-IgM, and pepC10-IgM antibodies. When used individually, the cutoff for each kinetic-EIA was set to generate 99% specificity. Utilizing logistic-likelihood regression analysis and receiver operating characteristic (ROC) techniques we determined that VlsE1-IgG, C6-IgG, and pepC10-IgM antibodies each contributed significant diagnostic information; a single-tier diagnostic score (DS) was generated for each sample using a weighted linear combination of antibody levels to these 3 antigens. DS performance was then compared to the STT and to MTT models employing different combinations of kinetic-EIAs. After setting the DS cutoff to match STT specificity (99%), the DS was 22.5% more sensitive than the STT for early-acute-phase disease (95% CI: 11.8% to 32.2%), 16.0% more sensitive for early-convalescent-phase disease (95% CI: 7.2% to 24.7%), and equivalent for detection of disseminated infection. The DS was also significantly more sensitive for early-acute-phase LD than MTT models whose specificity met or exceeded 99%. Prospective validation of this single-tier diagnostic score for Lyme disease will require larger studies using a broader range of potential cross-reacting conditions.

Integration of a Heparin-Induced Thrombocytopenia Order-Set (HITOS): A Retrospective Study

Introduction: Heparin-induced thrombocytopenia (HIT) may occur after exposure to heparin containing products. When HIT is suspected, early recognition and diagnosis is crucial due to the risk for developing a life-threatening thrombotic event that can lead to substantial morbidity and even death.However, making the diagnosis of HIT is challenging due to a high false positive rate associated with most widely used screening tests for HIT. Therefore, clinical assessment of the likelihood of HIT is essential to help guide the decision to order a HIT laboratory test and to make changes in anticoagulation management. In 2014, we integrated a new custom HIT Order-Set (HITOS) with the EPIC electronic medical record (EMR) system. HITOS requires a clinician seeking to order a HIT laboratory test to input data to calculate a 4Ts pretest likelihood score for HIT. Recommendations are then automatically provided for proceeding or not with the HIT test and for anticoagulant management. Specifically, for patients with a low likelihood of HIT, HITOS recommends continuing heparin without HIT testing. For patients with an intermediate or high likelihood, HITOS recommends discontinuing heparin in favor of an alternative anticoagulant and proceeding with HIT testing. Our study goals were to evaluate the effect of HITOS on patterns of HIT test ordering and on anticoagulation management in patients with suspected HIT.Methods: We performed a retrospective review of all inpatient charts in which an order for the laboratory test for HIT (heparin-PF4 antibody enzyme immunoassay) was recorded at Dartmouth Hitchcock Medical Center from December 2012 to December 2016. HITOS was launched in December 2014. Subjects were excluded from the study if their charts contained incomplete data, external laboratory results, previous documentation of a HIT diagnosis or duplicate testing . Data were extracted from the EMR for each study subject and included demographic information, clinical data, HIT test results and details of anticoagulation management before and after HIT laboratory testing. In the pre-HITOS group, the 4Ts score was applied retrospectively to assess the likelihood of HIT and was calculated independently by two study members. A score of ≤ 3 defined low likelihood for HIT; 4-5 points, intermediate; 6-8 points, high. The 4Ts score was obtained from the EMR in the post-HITOS group. Before and after HITOS comparisons were analyzed using the chi-square test for independence with a = 0.05.Results: A total of 465 EMR were reviewed; 401 subjects were included in the final analysis. The pre and post-HITOS groups included 213 and 189 subjects, respectively, with a similar median age (66 years, range 21 to 94 and 65 years, range 23 to 94). Pre-HITOS, a HIT test was ordered in 54% of low, 39% of intermediate and 7% of high likelihood cases. Post-HITOS, a HIT test was ordered in 30%, 57% and 14% of the respective cases (p <0.001 for each pre/post comparison). When there was at least an intermediate clinical likelihood for HIT, appropriate discontinuation of heparin at time of HIT testing occurred more frequently in the post-HITOS group (74% vs 66 %, respectively; p <0.001), and more patients in the post-HITOS group were accorded a clinical diagnosis of HIT than in the pre-HITOS group (11.1% vs 5.6%, respectively; p <0.05) group.Conclusions: Implementation of HITOS was associated with a decrease in HIT laboratory test ordering if the clinical likelihood for HIT was low and was associated with a higher rate of appropriate heparin discontinuation when the clinical likelihood of HIT was intermediate or high. Our results suggest that integration of HITOS may help refine the diagnostic process in patients with suspected HIT, though additional study will be required to evaluate the cost-effectiveness and effects on morbidity and mortality of this approach. DisclosuresNo relevant conflicts of interest to declare.

Laboratory Examination of Syphilis

Syphilis, is sexually transmitted disease caused by spirochete Treponema pallidum subsp.pallidum. It have many diverse clinical manifestations that occur in distinct stages. Early diagnosis and management are the main things to prevent transmission and complication. Direct test or morphological observation is the definitive diagnosis of syphilis. This can be done through animal inoculation test, dark field microscopy, direct fluorescence antibody (DFA), and nucleid acid amplification test (NAAT). While the indirect test is a nontreponemal serologic test consist of Wasserman test, venereal disease research laboratory (VDRL), toluidine red unheated serum test (TRUST), unheated serum reagin (USR), rapid plasma reagin (RPR) and treponemal serologic test, such as T. pallidum passive particle agglutination (TPPA), T. pallidum haemagglutination assay (TPHA), fluorescent treponemal antibody absorption (FTA-Abs), enzyme immunoassay (EIA) and rapid test. The algorithm of serologic test can be divided into traditional or reverse.

Laboratory Examination of Syphilis

Syphilis, is sexually transmitted disease caused by spirochete Treponema pallidum subsp.pallidum. It have many diverse clinical manifestations that occur in distinct stages. Early diagnosis and management are the main things to prevent transmission and complication. Direct test or morphological observation is the definitive diagnosis of syphilis. This can be done through animal inoculation test, dark field microscopy, direct fluorescence antibody (DFA), and nucleid acid amplification test (NAAT). While the indirect test is a nontreponemal serologic test consist of Wasserman test, venereal disease research laboratory (VDRL), toluidine red unheated serum test (TRUST), unheated serum reagin (USR), rapid plasma reagin (RPR) and treponemal serologic test, such as T. pallidum passive particle agglutination (TPPA), T. pallidum haemagglutination assay (TPHA), fluorescent treponemal antibody absorption (FTA-Abs), enzyme immunoassay (EIA) and rapid test. The algorithm of serologic test can be divided into traditional or reverse.

Limited Utility of Reverse Algorithm Syphilis Testing in HIV Clinic Among Men Who Have Sex With Men.

The reverse algorithm for syphilis diagnosis consists of a treponemal antibody screening immunoassay followed by confirmatory nontreponemal antibody testing. It is increasingly used in the United States despite studies suggesting limited cost-effectiveness in high-prevalence groups. In this retrospective cross-sectional study, we included men who have sex with men tested with the reverse algorithm in an Alabama HIV clinic between March 2015 and February 2017. Trep-Sure enzyme immunoassay (EIA) was used for the initial screen, followed by reflex nontreponemal reactive rapid plasma reagin (RPR) testing of specimens with positive results. Sociodemographic and clinical data were extracted from the electronic medical record and stratified according to EIA screen positivity. Quantitative EIA antibody index values were collected to assess test performance at various thresholds. Among 1693 men tested for syphilis with the reverse algorithm in HIV clinic, 808 (48%) had a positive initial EIA screen. A majority (53%) of men with subsequent RPR testing had a nonreactive RPR (EIA+/RPR-), and 19% (19/98) of these EIA+/RPR- samples tested had a negative confirmatory Treponema pallidum particle agglutination testing result. Analysis of quantitative EIA index values using a receiver operating characteristics curve suggested that a threshold >8 (rather the current threshold of antibody index 1.2) improved the performance of the test. Among men who have sex with men tested in HIV clinic, the syphilis reverse algorithm was inefficient because of high rates of prior syphilis and false-positive EIA screening. Frequent syphilis screening in high-prevalence populations is an important part of the US epidemic response, and the traditional algorithm is preferred.

Evaluation of the effectiveness of treatment of patients with COVID-19 on the results of a laboratory study

The emergence of a new coronavirus infection was marked by the re-profiling of hospitals, including infectious diseases, to treat this category of patients. The accumulation of information about the effectiveness of its treatment is of scientific and practical interest. Purpose of the study : to evaluate the diagnosis and effectiveness of treatment of patients with COVID-19 Based on the results of laboratory tests. Materials and methods . The study was conducted in the period from 18.04.20 to 19.06.20, 379 patients were included in the study. Upon admission to the hospital, 27 patients had a positive nasal and pharyngeal swab by PCR for SARS-CoV-2 RNA, the results of MSCT of the OGC in 368 (99,5±0,38%) patients indicated the presence of pneumonia. On the first day of hospitalization, positive smears for SARS-CoV-2 RNA were in 172 (46,5±0,3%) patients, on the third day – in 96 (25,9±2,28%) patients. Patients with negative PCR results underwent enzyme immunoassay for IgM antibodies to SARS-CoV-2, in 108 (28,5±2,3%) they were found. Results. Upon admission to the hospital, a confirmed new coronavirus infection COVID-19 was observed only in 7,1±1,3%, in all the remaining 92,8±1,3% the diagnosis was probable. The majority of patients had MSCT results on admission. Novel coronavirus infection COVID-19 was not confirmed in 9,7±1,5% of hospitalized patients. All laboratory facilities were used for diagnostics. Confirmation of the disease based on the results of PCR diagnostics of nasal and nasopharyngeal swabs was achieved in 83,6±1,1%, and during the enzyme immunoassay for IgM antibodies to SARS-CoV-2 coronavirus – in 108 (28,5±2,3%) sick. The control X-ray examination of the chest organs showed positive dynamics in most patients (252; 71,6±2,4%). Some patients experienced the presence of the virus in the nose and nasopharynx after 12 days of treatment. Treatment times for smear-positive patients on days 10 and 12 were lengthened. The average number of days of inpatient treatment of patients with detected coronavirus infection with manifestations of pneumonia was 18±2,1 bed/days . Conclusion . In all patients who have a clinic of acute respiratory viral infection, it is necessary to diagnose a new coronavirus infection COVID-19 not only by PCR diagnostics, but also to use an enzyme-linked immunosorbent assay for SARS-CoV-2, with mandatory X-ray examination of the chest organs MSCT.

Serological diagnosis of Mycobacterium avium complex lung diseases by enzyme immunoassay of IgA antibodies against MAC-specific glycopeptidolipid core antigen

IntroductionThere is an increasing trend worldwide in the incidence of Mycobacterium avium complex pulmonary diseases (MAC-PD) and the diagnosis is sometimes complicated. Recently, an enzyme immunoassay (EIA) kit that detects serum IgA antibody against MAC-specific glycopeptidolipid (GPL) core antigen had been developed and found to be useful in discriminating MAC-PD from other lung diseases. The antibody was subsequently also found to be elevated in patients suffering Mycobacterium abscessus pulmonary diseases (MAB-PD). This study is to evaluate this EIA kit in the serological diagnosis of MAC-PD in Hong Kong Chinese patients. MethodsThe study was conducted in Grantham Hospital, Hong Kong between July 2017 and July 2018. Assay of the IgA antibody level using the EIA kit was done on blood samples collected from patients suffering from MAC-PD, MAB-PD, pulmonary tuberculosis and other lung diseases. ResultsThere were 100 subjects recruited into the study, among which 11 were excluded. By using the cut-off value 0.7 U/mL provided by the manufacturer, the sensitivity and specificity for diagnosis were 73.7% and 77.6% for MAC-PD; 50% and 77.6% for MAB-PD. By receiver operating characteristic curves analysis, new cut-off for MAC-PD and MAB-PD were calculated as 1.771 U/mL and 0.172 U/m, respectively. The sensitivity and specificity were 68.4% and 86.2% for MAC-PD, whereas 66.7% and 72.4% for MAB-PD. ConclusionsOur study showed that the enzyme immunoassay of IgA antibodies against MAC-specific glycopeptidolipid core antigen could help to distinguishing MAC and M. abscessus pulmonary diseases from pulmonary tuberculosis and other lung diseases among Hong Kong Chinese patients. Further larger scale studies in our local population for the usefulness of this antibody test in the diagnosis and monitoring of MAC and M. abscessus lung diseases might be warranted.

Sensitivity and specificity of different antibody tests for detecting varicella-zoster virus

IntroductionAntibody tests for detecting varicella-zoster virus include the fluorescent-antibody-to-membrane-antigen (FAMA) assay, immune adherence hemagglutination assay (IAHA), enzyme immunoassay (EIA), and the glycoprotein-based enzyme-linked immunosorbent assay (gpELISA). Although FAMA and gpELISA are highly sensitive, FAMA is not available commercially. Therefore, this study was performed to compare potential high-sensitivity tests with commercially available tests. MethodsFour antibody tests, FAMA, gpELISA, EIA, and IAHA, were performed using sera collected from 32 children aged 7 months–10 years. Using FAMA as a reference, the sensitivity and specificity of gpELISA, EIA, and IAHA were assessed. Subsequently, using gpELISA as a reference, the positive agreement rate of EIA and IAHA was assessed. ResultsOn a reference scale with FAMA set at 100%, the sensitivity and specificity of the antibody tests were as follows: gpELISA, 67% and 100%; EIA, 67% and 100%; and IAHA, 47% and 100%, respectively. The positive agreement rates of EIA and IAHA relative to gpELISA were 86% and 64%, respectively.Conclusions: gpELISA had a lower positive rate than did FAMA, and showed comparable sensitivity to that of EIA.

Recent Advances in Diagnostic Approaches for Epstein-Barr Virus.

Epstein–Barr virus (EBV) is the causative agent of many diseases including infectious mononucleosis (IM), and it is associated with different subtypes of lymphoma, sarcoma and carcinoma such as Hodgkin’s lymphoma, non-Hodgkin’s lymphoma, nasopharyngeal carcinoma, and gastric carcinoma. With the advent of improved laboratory tests for EBV, a timelier and accurate diagnosis could be made to aid better prognosis and effective treatment. For histopathological lesions, the in situ hybridization (ISH) of EBV-encoded RNA (EBER) in biopsy tissues remains the gold standard for detecting EBV. Methods such as the heterophile antibody test, immunofluorescence assays, enzyme immunoassays, Western blot, and polymerase chain reaction (PCR) are also employed in the detection of EBV in different types of samples. The determination of EBV viral load using PCR, however, is gaining more prominence in the diagnosis of EBV-associated diseases. Given the challenge of false positive/negative results that are sometimes experienced during the detection of EBV, variability in results from different laboratories, and the impact of factors such as sample type and the immunological status of patients from whom samples are collected, the need to critically examine these present methods is invaluable. This review thus presents current advances in the detection of EBV, detailing the advantages and disadvantages of the various techniques. In addition, fundamental virological concepts are highlighted to enhance the greater understanding, the proper application, and the interpretation of EBV tests.

Screening Donated Blood for Transfusion-Transmissible Cytomegalovirus Infection among Libyans

Human cytomegalovirus (HCMV) is a ubiquitous DNA-containing herpesvirus causes severe and fatal diseases in immunocompromised patients and a prevalent cause of virus-associated birth defects. Blood transfusion donated for neonates, pregnant women, and immunocom-promised patients should be adequately screened for evidences of CMV infection prior to use in clinical management. The effective national programmes for quality-assured screening of donated blood have not yet been fully established, hence this study was undertaken to assess whether any bloodborne-CMV infections pose a significant threat to the safety of the blood supplies. A total of 200 voluntary blood donor subjects admitted to the Blood Bank of Benghazi/Libya were screened for transfusion-transmissible CMV (TT-CMV) using a highly sensitive CMV total IgG and IgM antibody enzyme immunoassay as well as CMV pp65 anti-genemia assays. We determined that the overall seropositivity for IgG antibodies (80.50%) was higher than that of IgM antibodies (39.00%), but only 2 (1.00%) individuals out of these donors were seropositive for the CMV-antigenic protein pp65. The frequency of CMV infection based on gender was incomparable due to the small population number of blood-donated females. According to age, there was not influence of various age groups on prevalence of anti-CMV IgG antibodies, while a progressive increase in seropositivity of CMV-IgM antibodies with age was detected. The age groups were not significantly associated with CMV prevalence. In contrast, only 2 (1.00%) patients were shown to be positive for all three performed assays indicating a recurrent infection. Our findings prove a risk of primary transfusion-associated transmission of CMV and may provide a policy guidance on ensuring safe blood supplies accessible to all patients who require transfusion.

Immunity to varicella zoster virus among pregnant women in the Norwegian Mother and Child Cohort Study.

IntroductionInfection with varicella zoster virus (VZV) in pregnancy may lead to serious outcomes both for the mother and the newborn. Targeted screening and vaccination of non-immune women during reproductive age could prevent varicella infection in pregnancy. Currently, no universal varicella screening of pregnant women is implemented in Norway, but serological testing in pregnancy is recommended in particular situations. We examined seroprevalence of VZV in a national pregnancy cohort in order to help assess a need for VZV screening of women during reproductive age.MethodsWe determined the susceptibility to VZV and the reliability of self-reported history of VZV infection in the Norwegian obstetric population by using a random sample of 1,184 pregnant women from the Norwegian Mother and Child Cohort study (MoBa). The MoBa study included approximately 95,200 pregnant women in Norway between 1998 and 2009. Blood samples taken at gestational week 17–18 were analysed using a commercial enzyme immunoassay for specific IgG antibodies to Varicella-Zoster virus. Second sample taken at birth was tested if the first sample result was negative or equivocal.ResultsOf the 1,184 pregnant women, 98.6% (n = 1,167) were seropositive, 0.83% (n = 10) remained seronegative, and four women (0.34%) seroconverted during their pregnancy. No significant associations were found between serological status and women’s age at birth, gestational age, women’s country of birth and year of child’s birth. One woman reported prior history of varicella, whereas 143 (12.1%) women reported a household exposure to childhood diseases with fever and rash, of which 25 reported exposure to varicella, of which all were seropositive.ConclusionsThe findings support antenatal screening recommendations in Norway advising testing for VZV in pregnant women with unknown immunity to VZV. Further studies are however needed to better identify target groups for screening and vaccination.

Development of an Anti-Idiotypic VHH Antibody and Toxin-Free Enzyme Immunoassay for Ochratoxin A in Cereals.

Enzyme-linked immunosorbent assay (ELISA) test kits have been widely used for the determination of mycotoxins in agricultural products and foods, however, this test uses toxin standards with high toxicity and carcinogenicity that seriously threaten human health. In this work, the anti-idiotypic nanobody VHH 2-24 was first developed and then, using it as a surrogate standard, a toxin-free enzyme immunoassay for ochratoxin A (OTA) was established. The IC50 value of the VHH 2-24 surrogate standard-based ELISA was 0.097 µg/mL, with a linear range of 0.027–0.653 µg/mL. The average recoveries were tested by spike-and-recovery experiments, and ranged from 81.8% to 105.0%. The accuracy of the developed ELISA for detecting OTA was further verified by using the high performance liquid chromatography (HPLC) method, and an excellent correlation was observed. In summary, the toxin-free ELISA established in this study proves the latent use of the anti-idiotypic VHH as a surrogate calibrator for other mycotoxins and highly toxic small molecule analysis to improve assay properties for highly sensitive analyte determination in agricultural products.

Accuracy of a Novel Histoplasmosis Enzyme Immunoassay to Evaluate Suspicious Lung Nodules.

Granulomas caused by infectious lung diseases present as indeterminate pulmonary nodules (IPNs) on radiography. Newly available serum enzyme immunoassay (EIA) for histoplasmosis has not been studied for the evaluation of IPNs. We investigated serum biomarkers of histoplasmosis antibodies as an indication of benign disease in IPNs from a highly endemic region. A total of 152 serum samples from patients presenting with pulmonary nodules ≤30 mm in maximum diameter were analyzed for histoplasmosis antibodies by immunodiffusion and EIA IgG and IgM tests. Serology and FDG-PET/CT scan diagnostic test characteristics were estimated and compared. Cancer prevalence was 55% (n = 83). Thirty-nine (26%) individuals were positive for IgG histoplasmosis antibodies. Twelve samples were IgM antibody positive. Immunodiffusion serology was similar to IgM antibody results with 13 positive tests. Diagnostic likelihood ratios for benign disease were 0.62, 0.33, and 0.28 for FDG-PET/CT, IgG, and IgM antibodies, respectively. When both IgG and IgM were positive (n = 8), no nodules were cancerous and six were FDG-PET/CT avid. A positive EIA test for both IgM and IgG strongly suggested histoplasmosis etiology and benign granuloma for 12% of benign nodules arising from a highly endemic region. Presence of either IgG or IgM histoplasma antibodies was associated with benign disease. The EIA test was more sensitive in assessing histoplasma exposure than immunodiffusion serology. A new CLIA-certified histoplasmosis antibody EIA test measures histoplasmosis exposure, offers a possible alternative clinical diagnosis for benign IPNs, and may improve IPN evaluation while avoiding harmful invasive biopsies.