scholarly journals Development and Clinical Evaluation of a Recombinant-Antigen-Based Cytomegalovirus Immunoglobulin M Automated Immunoassay Using the Abbott AxSYM Analyzer

2000 ◽  
Vol 38 (4) ◽  
pp. 1476-1481 ◽  
Author(s):  
G. T. Maine ◽  
R. Stricker ◽  
M. Schuler ◽  
J. Spesard ◽  
S. Brojanac ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Clinical Evaluation ◽  
Measles Virus ◽  
Parvovirus B19 ◽  
Relative Sensitivity ◽  
Cross Reactivity ◽  
Immunoglobulin M ◽  
Cmv Infection ◽  
Varicella Zoster ◽  
Sensitivity Specificity

A new microparticle enzyme immunoassay (MEIA), the Cytomegalovirus (CMV) Immunoglobulin M (IgM) test, was developed on the Abbott AxSYM analyzer. This test uses recombinant CMV antigens derived from portions of four structural and nonstructural proteins of CMV: pUL32 (pp150), pUL44 (pp52), pUL83 (pp65), and pUL80a (pp38). A total of 1,608 specimens from random volunteer blood donors (n = 300), pregnant women (n = 1,118), transplant recipients (n = 6), and patients with various clinical conditions and disease states (n = 184) were tested during development and evaluation of this new assay. In a preliminary clinical evaluation we tested specimens collected prospectively from pregnant women (n = 799) and selected CMV IgM-positive archived specimens from pregnant women (n = 39). The results from the new CMV IgM immunoassay were compared to the results of a consensus interpretation of the results obtained with three commercial CMV IgM immunoassays. The results for specimens with discordant results were resolved by a CMV IgM immunoblot assay. The relative sensitivity, specificity, and agreement for the AxSYM CMV IgM assay were 94.29, 96.28, and 96.19%, respectively, and the resolved sensitivity, specificity, and agreement were 95.83, 97.47, and 97.37%, respectively. We also tested serial specimens from women who experienced seroconversion or a recent CMV infection during gestation (n = 17) and potentially cross-reactive specimens negative for CMV IgM antibody by the consensus tests (n = 184). The AxSYM CMV IgM assay was very sensitive for the detection of CMV IgM during primary CMV infection, as shown by the detection of CMV IgM at the same time as or just prior to the detection of CMV IgG. Specimens from individuals with lupus (n = 16) or parvovirus B19 infection (n = 6) or specimens containing hyper IgM (n = 9), hyper IgG (n = 8), or rheumatoid factor (n = 55) did not cross-react with the AxSYM assay. One specimen each from individuals infected with Epstein-Barr virus (n = 26), measles virus (n = 10), herpes simplex virus (n = 12), or varicella-zoster virus (n = 13) infection, one specimen from an influenza vaccinee (n = 14), and one specimen containing antinuclear antibody cross-reacted with the assay. The overall rate of cross-reactivity of the specimens with the assay was 3.3% (6 of 184). The AxSYM CMV IgM assay is a sensitive and specific assay for the detection of CMV-specific IgM.

scholarly journals Recombinant Antigens To Detect Toxoplasma gondii-Specific Immunoglobulin G and Immunoglobulin M in Human Sera by Enzyme Immunoassay

2000 ◽  
Vol 38 (3) ◽  
pp. 1144-1150 ◽  
Author(s):  
D. Aubert ◽  
G. T. Maine ◽  
I. Villena ◽  
J. C. Hunt ◽  
L. Howard ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Immunoglobulin G ◽  
Acute Infection ◽  
Relative Sensitivity ◽  
Immunoglobulin M ◽  
Recombinant Antigens ◽  
Disease Spectrum ◽  
Human Sera ◽  
Acute Toxoplasmosis ◽  
Sensitivity Specificity

We have evaluated the diagnostic utility of eleven Toxoplasma gondii recombinant antigens (P22 [SAG2], P24 [GRA1], P25, P28 [GRA2], P29 [GRA7], P30 [SAG1], P35, P41 [GRA4], P54 [ROP2], P66 [ROP1], and P68) in immunoglobulin G (IgG) and IgM recombinant enzyme-linked immunosorbent assays (Rec-ELISAs). Following an initial evaluation, six recombinant antigens (P29, P30, P35, P54, P66, and P68) were tested in the IgG and IgM Rec-ELISAs with four groups of samples which span the toxoplasmosis disease spectrum (negative, chronic infection, acute infection, and recent seroconversion). Our results suggest that the combination of P29, P30, and P35 in an IgG Rec-ELISA and the combination of P29, P35, and P66 in an IgM Rec-ELISA can replace the tachyzoite antigen in IgG and IgM serologic tests, respectively. The relative sensitivity, specificity, and agreement for the IgG P29-P30-P35 Rec-ELISA were 98.4, 95.7, and 97.2%, respectively. The resolved sensitivity, specificity, and agreement for the IgM P29-P35-P66 Rec-ELISA were 93.1, 95.0, and 94.5%, respectively. Relative to the tachyzoite-based immunocapture IgM assay, the IgM P29-P35-P66 Rec-ELISA detects fewer samples that contain IgG antibodies with elevated avidity from individuals with an acute toxoplasmosis.

scholarly journals Comparison of a Baculovirus-Based VP2 Enzyme Immunoassay (EIA) to an Escherichia coli-Based VP1 EIA for Detection of Human Parvovirus B19 Immunoglobulin M and Immunoglobulin G in Sera of Pregnant Women

2000 ◽  
Vol 38 (4) ◽  
pp. 1472-1475 ◽  
Author(s):  
Jeanne A. Jordan
Keyword(s):  
Escherichia Coli ◽  
Pregnant Women ◽  
Enzyme Immunoassay ◽  
Clinical Performance ◽  
Parvovirus B19 ◽  
Initial Study ◽  
Immunoglobulin M ◽  
Viral Capsid ◽  
Human Parvovirus B19 ◽  
Viral Capsid Antigen

A split-sample study was conducted to evaluate the clinical performance of an enzyme immunoassay that detects the human parvovirus B19 virus (B19V) immunoglobulin M (IgM) or IgG in the sera of pregnant women. The initial study compared a baculovirus-expressed VP2 enzyme immunoassay (BVP2 EIA) (Biotrin International Inc., Dublin, Ireland) with the currently available and commonly used Escherichia coli-expressed VP1 enzyme immunoassay (EVP1 EIA) (MRL Diagnostics, Cypress, Calif.). There was a high degree of agreement between the two assays in the detection of IgM antibodies (283 of 307 [92.2%]) or IgG antibodies (279 of 311 [89.7%]), with the majority of discrepancies (IgM, 17 of 24 [71%]; IgG, 16 of 31 [50%]) being due to equivocal data obtained with the EVP1 EIA. Specimens with discordant BVP2 EIA and EVP1 EIA results (23 of 24 IgM and 32 of 32 IgG results) were analyzed further by baculovirus-based VP1 immunofluorescence assays (BVP1 IFAs) (Biotrin International). The BVP2 EIA and BVP1 IFA results for 20 of 23 and 28 of 32 specimens for IgM and IgG, respectively, were concordant. In contrast, the EVP1 EIA and BVP1 IFA data for only 3 of 23 and 4 of 32 specimens for IgM and IgG, respectively, were in agreement, despite the fact that the same capsid antigen was used. Both the BVP2 EIAs and BVP1 IFAs utilize a conformational viral capsid antigen, while the EVP1 EIA uses a denatured viral capsid antigen. In conclusion, the BVP2 EIAs produced far fewer equivocal results for IgM and IgG, correlating more closely to the confirmatory BVP IFAs, than did the EVP1 EIAs and proved to be more accurate for detecting B19V antibodies in the sera of pregnant women.

scholarly journals Evaluation of the Abbott AxSYM Cytomegalovirus (CMV) Immunoglobulin M (IgM) Assay in Conjunction with Other CMV IgM Tests and a CMV IgG Avidity Assay

2001 ◽  
Vol 8 (1) ◽  
pp. 196-198 ◽  
Author(s):  
T. Lazzarotto ◽  
C. Galli ◽  
R. Pulvirenti ◽  
R. Rescaldani ◽  
R. Vezzo ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Accurate Diagnosis ◽  
Immunoglobulin M ◽  
Igg Antibodies ◽  
Cmv Infection ◽  
Avidity Assay ◽  
Igg Avidity ◽  
Avidity Test ◽  
Reflex Testing ◽  
Initial Reactivity

ABSTRACT The measurement of the avidity of cytomegalovirus (CMV) immunoglobulin G (IgG) antibodies has been shown by several investigators to be useful in identifying and excluding primary CMV infections in pregnant women. In this work, we examined the diagnostic utility of reflex testing of CMV IgM-positive specimens from pregnant women by using a CMV IgG avidity assay. The utility of this approach was directly dependent on the sensitivity of the CMV IgM assay employed during the initial screen. The higher initial reactivity rate of the AxSYM CMV IgM assay was necessary in order to detect CMV IgM in specimens containing low-avidity CMV IgG antibodies, indicative of a primary CMV infection, which other CMV IgM assays (Behring, Vidas, Captia, and Eurogenetics) fail to detect in some cases. The use of the AxSYM CMV IgM assay, followed by an avidity test, should result in more accurate diagnosis of CMV infection in pregnant women.

scholarly journals A novel multiplexed Enzyme-Linked Immunosorbent Assay for the detection of IgG seroreactivity to cytomegalovirus (CMV) UL144

2021 ◽  
Author(s):  
H Miller ◽  
P Simpson ◽  
M Forman ◽  
A Prigan ◽  
S Kehl ◽  
...  
Keyword(s):  
Immunosorbent Assay ◽  
Natural Infection ◽  
Epidemiological Studies ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Clinical Microbiology Laboratory ◽  
Cmv Infection ◽  
Predictive Values ◽  
Specific Strain ◽  
Sensitivity Specificity

Infection with human cytomegalovirus (CMV) is common and may have grave consequences in transplant recipients and congenitally infected children. Diagnosis of CMV infection is based on detection of specific antibodies and molecular assays. The incorporation of CMV serological assays into diagnostic algorithms requires careful evaluation and interpretation. Very few serological assays measure CMV infection by a specific strain. We developed an enzyme-linked immunosorbent assay (ELISA) using CMV-encoded UL144 as antigen. UL144 encodes for three major genotypes, A, B and C, and recombinants. The ELISA was developed with the three UL144 proteins and optimized as a multiplex assay. Sera from 55 positive and 59 negative CMV IgG, determined by the clinical microbiology laboratory, were used for evaluation and optimization. A cutoff optical density (OD) that distinguishes UL144 antibody-positive from -negative sera was established. Sera detected UL144 A, B, C and combination of these antigens. Assay threshold of 0.1 was established, and from a total of 303 sera, the overall sensitivity, specificity, positive and negative predictive values of the multiplex ELISA were 86.72% (95% CI 79.59% to 92.07%), 96.57% (92.69% to 98.73%), 94.40% (88.45% to 97.38%), and 91.60% (87.50% to 94.44%). The inter- and intraassay median coefficients of variation were 0.06 (IQR 0.56, 0.2) and 0.171 (IQR 0.038, 0.302). No cross reactivity was observed with HSV-positive CMV-negative sera. This ELISA gives simple and reproducible results for detection of anti-CMV UL144 IgG. It may assist in differentiating natural infection from CMV vaccines that lack UL144, and may provide an important tool for epidemiological studies of CMV strains.

scholarly journals Quantitative measurement of anti-SARS-CoV-2 antibodies: Analytical and clinical evaluation

2021 ◽  
Author(s):  
Victoria Higgins ◽  
Anselmo Fabros ◽  
Vathany Kulasingam
Keyword(s):  
Antibody Response ◽  
Clinical Evaluation ◽  
Predictive Value ◽  
Cross Reactivity ◽  
Analytical Sensitivity ◽  
Past Infection ◽  
Clinical Sensitivity ◽  
Limit Of Quantitation ◽  
Sensitivity Specificity ◽  
Roche Diagnostics

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of Coronavirus Disease 2019 (COVID-19). While molecular-based testing is used to diagnose COVID-19, serologic testing of antibodies specific to SARS-CoV-2 is used to detect past infection. While most serologic assays are qualitative, a quantitative serologic assay was recently developed that measures antibodies against the S protein, the target of vaccines. Quantitative antibody determination may help determine antibody titer, facilitate longitudinal monitoring of the antibody response, including antibody response to vaccines. We evaluated the quantitative Roche Elecsys® Anti-SARS-CoV-2 S assay. Specimens from 167 PCR-positive patients and 103 control specimens were analyzed using the Elecsys® Anti-SARS-CoV-2 S assay on the cobas e411 (Roche Diagnostics). Analytical evaluation included assessing linearity, imprecision, and analytical sensitivity. Clinical evaluation included assessing clinical sensitivity, specificity, cross-reactivity, positive predictive value (PPV), negative predictive value (NPV), and serial sampling from the same patient. The Elecsys® Anti-SARS-CoV-2 S assay exhibited highest sensitivity of 84.0% 15-30 days post-PCR positivity, no cross-reactivity, specificity and PPV of 100%, and NPV between 98.3%-99.8% ≥14 days post-PCR positivity, depending on the seroprevalence estimate. Imprecision was <2% at 9.06 U/mL across 6 days, the negative QC was consistently negative (<0.40 U/mL), the manufacturer’s claimed limit of quantitation of 0.40 U/mL was verified, and linearity across the analytical measuring range was observed, except at the low end (<20 U/mL). Lastly antibody response showed high inter-individual variation in level and time of peak antibody titre and trends over time.

scholarly journals Analysis of a Routinely Used Commercial Anti-Chikungunya IgM ELISA Reveals Cross-Reactivities with Dengue in Brazil: A New Challenge for Differential Diagnosis?

Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 819
Author(s):  
Monique da Rocha Queiroz Lima ◽  
Raquel Curtinhas de Lima ◽  
Elzinandes Leal de Azeredo ◽  
Flavia Barreto dos Santos
Keyword(s):  
Disease Surveillance ◽  
Endemic Area ◽  
Chikungunya Virus ◽  
Elisa Test ◽  
Cross Reactivity ◽  
Immunoglobulin M ◽  
Diagnostic Tools ◽  
Healthy Individuals ◽  
Denv Serotypes ◽  
Igm Elisa

In Brazil, chikungunya emerged in 2014, and by 2016, co-circulated with other arbovirosis, such as dengue and zika. ELISAs (Enzyme-Linked Immunosorbent Assays) are the most widely used approach for arboviruses diagnosis. However, some limitations include antibody cross reactivities when viruses belong to the same genus, and sensitivity variations in distinct epidemiological scenarios. As chikungunya virus (CHIKV) is an alphavirus, no serological cross reactivity with dengue virus (DENV) should be observed. Here, we evaluated a routinely used chikungunya commercial IgM (Immunoglobulin M) ELISA test (Anti-Chikungunya IgM ELISA, Euroimmun) to assess its performance in confirming chikungunya in a dengue endemic area. Samples (n = 340) representative of all four DENV serotypes, healthy individuals and controls were tested. The Anti-CHIKV IgM ELISA test had a sensitivity of 100% and a specificity of 25.3% due to the cross reactivities observed with dengue. In dengue acute cases, the chikungunya test showed an overall cross-reactivity of 31.6%, with a higher cross-reactivity with DENV-4. In dengue IgM positive cases, the assay showed a cross-reactivity of 46.7%. Serological diagnosis may be challenging and, despite the results observed here, more evaluations shall be performed. Because distinct arboviruses co-circulate in Brazil, reliable diagnostic tools are essential for disease surveillance and patient management.

scholarly journals Low Maternal Immunoglobulin G Avidity and Single Parity as Adverse Implications of Human Cytomegalovirus Vertical Transmission in Pregnant Women with Immunoglobulin M Positivity

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 866
Author(s):  
Masatoki Kaneko ◽  
Junsuke Muraoka ◽  
Kazumi Kusumoto ◽  
Toshio Minematsu
Keyword(s):  
Risk Factors ◽  
Pregnant Women ◽  
Vertical Transmission ◽  
Human Cytomegalovirus ◽  
Multiple Logistic Regression Analysis ◽  
Clinical Signs ◽  
Immunoglobulin M ◽  
Igg Antibody ◽  
Neurological Sequelae ◽  
Previous Pregnancy

Human cytomegalovirus (CMV) is the leading cause of neurological sequelae in infants. Understanding the risk factors of primary CMV infection is crucial in establishing preventive strategies. Thus, we conducted a retrospective cohort study to identify risk factors of vertical transmission among pregnant women with immunoglobulin (Ig) M positivity. The study included 456 pregnant women with IgM positivity. Information on age, parity, occupation, clinical signs, IgM levels, and IgG avidity index (AI) was collected. The women were divided into infected and non-infected groups. The two groups showed significant differences in IgM level, IgG AI, number of women with low IgG AI, clinical signs, and number of pregnant women with single parity. In the multiple logistic regression analysis, pregnant women with single parity and low IgG AI were independent predictors. Among 40 women who tested negative for IgG antibody in their previous pregnancy, 20 showed low IgG AI in their current pregnancy. Among the 20 women, 4 had vertical transmission. These results provide better understanding of the risk factors of vertical transmission in pregnant women with IgM positivity.

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