scholarly journals High prevalence of false positive SARS-CoV2 serology in a cohort of patients with liver autoimmune diseases

2021 ◽  
pp. 372-377
Author(s):  
Maria Giulia Cornacchia ◽  
Moris Sangineto ◽  
Rosanna Villani ◽  
Francesco Cavallone ◽  
Giuseppe Di Gioia ◽  
...  
Keyword(s):  
Autoimmune Diseases ◽  
False Positive ◽  
Serological Test ◽  
High Rate ◽  
Antibody Detection ◽  
Primary Biliary Cholangitis ◽  
Serological Response ◽  
Positive Serology ◽  
Serological Tests ◽  
False Positivity

Aim Monitoring the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) immunization in patients with autoimmune diseases is of particular concern to understand their response to the infection and to the vaccine. In fact, the immunological disorder and the immunosuppressive therapies could affect the serological response. SARS-CoV2 serological tests potentially provide this information, although they were rapidly commercialized with internal verifications. Here, we analysed the seroprevalence to SARS-CoV2 in a cohort of patients with liver autoimmune diseases. Methods From May to December 2020, a cohort of patients affected by primary biliary cholangitis (PBC), autoimmune hepatitis (AIH) and PBC/AIH overlap syndrome were screened with (reverse transcription-polymerase chain reaction) RT-PCR of nasopharyngeal swabs, rapid antigenic test and chemiluminescent serological test during routine follow-up. Results The analysis of 42 patients was carried out: 18 (42.85%) PBC, 12 (28.57%) AIH and 12 (28.57%) PBC/AIH overlap syndromes. Only 2 patients (4.76%) resulted positive to the RNA, antigen and antibody detection tests, hence affected by SARS-CoV2 infection. 14 subjects out of 40 negative cases presented a positive serology for SARS-CoV2 antibodies, hence with a false positivity in the 35% of cases without infection. Among these, 6 (42.86%) patients presented only immunoglobulin (Ig)M positivity, 6 (42.86%) patients presented positivity for only IgG and 2 (14.28%) patients were positive to both IgM and IgG. Notably, the presence of autoantibodies did not correlate with the serological false positivity, highlighting that there is no cross-reactivity with autoantibodies. The presence of polyclonal hypergammaglobulinemia did not interfere with the serological test as well. Interestingly, the patients with false positive serology showed higher levels of gamma-glutamyltransferase (GGT) and C-reactive protein (CRP). Conclusions Patients with liver autoimmune diseases present a high rate of false positive SARS-CoV2 serology. Therefore, new strategies are needed to study the serological response in this patient category.

scholarly journals Efficacy of Several Serological Tests and Antigens for Diagnosis of Bovine Brucellosis in the Presence of False-Positive Serological Results Due to Yersinia enterocolitica O:9

2005 ◽  
Vol 12 (1) ◽  
pp. 141-151 ◽  
Author(s):  
P. M. Muñoz ◽  
C. M. Marín ◽  
D. Monreal ◽  
D. González ◽  
B. Garin-Bastuji ◽  
...  
Keyword(s):  
Yersinia Enterocolitica ◽  
False Positive ◽  
Lipid A ◽  
Protein Complexes ◽  
Serological Test ◽  
Bovine Brucellosis ◽  
Serological Tests ◽  
Cytosolic Proteins ◽  
Membrane Protein Complexes ◽  
Sensitivity Specificity

ABSTRACT Yersinia enterocolitica O:9 bears a smooth lipopolysaccharide (S-LPS) of Brucella sp. O-chain A + C/Y epitopic structure and is a cause of false-positive serological reactions (FPSR) in standard tests for cattle brucellosis. Brucella S-LPS, cross-reacting S-LPSs representing several O-chain epitope combinations, Brucella core lipid A epitopes (rough LPS), Brucella abortus S-LPS-derived polysaccharide, native hapten polysaccharide, rough LPS group 3 outer membrane protein complexes, recombinant BP26, and cytosolic proteins were tested in enzyme-linked immunosorbent assays (ELISA) and precipitation tests to detect cattle brucellosis (sensitivity) and to differentiate it from FPSR (specificity). No single serological test and antigen combination showed 100% sensitivity and specificity simultaneously. Immunoprecipitation tests with native hapten polysaccharide, counterimmunoelectrophoresis with cytosolic proteins, and a chaotropic ELISA with Brucella S-LPS were 100% specific but less sensitive than the Rose Bengal test, complement fixation, and indirect ELISA with Brucella S-LPSs and native hapten or S-LPS-derived polysaccharides. A competitive ELISA with Brucella S-LPS and M84 C/Y-specific monoclonal antibody was not 100% specific and was less sensitive than other tests. ELISA with Brucella suis bv. 2 S-LPS (deficient in C epitopes), Escherichia hermannii S-LPSs [lacking the contiguous α-(1-2)-linked perosamine residues characteristic of Y. enterocolitica S-LPS], BP26 recombinant protein, and Brucella cytosolic fractions did not provide adequate sensitivity/specificity ratios. Although no serological test and antigen combination fully resolved the diagnosis of bovine brucellosis in the presence of FPSR, some are simple and practical alternatives to the brucellin skin test currently recommended for differential diagnosis.

scholarly journals Canine brucellosis: bacteriological and serological investigation of naturally infected dogs in Mexico City

1977 ◽  
Vol 6 (6) ◽  
pp. 591-597
Author(s):  
R Flores-Castro ◽  
F Suarez ◽  
C Ramirez-Pfeiffer ◽  
L E Carmichael
Keyword(s):  
Mexico City ◽  
Serological Test ◽  
High Rate ◽  
Serological Tests ◽  
High Prevalence ◽  
Genital Tract Infections ◽  
Health Significance ◽  
Bacteriological Investigation ◽  
Tract Infections ◽  
Canine Brucellosis

Bacteriological investigation of canine brucellosis in Mexico City revealed a high rate (11.8%) of Brucella canis infection in a sampling of 59 stray dogs. When conservative criteria were employed in the interpretation of serological test results, there was general agreement between the serological and bacteriological findings; however, some animals with localized male genital tract infections could not be judged as infected solely by serological tests. All Mexican field isolates were identified as B. canis; however, some diversity was observed as regards nitrate reduction, growth in the presence of basic fuchsine, and the degree of mucoidness. The seemingly high prevalence of B. canis infection in Mexico City dogs suggests the need for further inquiry into the possible public health significance.

scholarly journals Brucellosis Spondylodiscitis: A case report

2020 ◽  
pp. 92-97
Keyword(s):  
Musculoskeletal Pain ◽  
Serological Test ◽  
Clinical Manifestations ◽  
Animal Husbandry ◽  
Clinical Suspicion ◽  
Diagnostic Methods ◽  
Positive Serology ◽  
Serological Tests ◽  
Regular Treatment ◽  
Negative Results

Brucellosis is an endemic disease in Iran that is transmitted from animal to human. The clinical manifestations of brucellosis are nonspecific and its complications involve bones and joints. Brucellosis osteomyelitis can mimic the manifestations of neoplasms; therefore, it cannot readily be diagnosed in some cases. Under such circumstances, high incidence can be a helpful factor. We reported a 49-year-old man patient who presented with chronic musculoskeletal pain in the lower back. Initially, he was treated for osteoarthritis due to several negative serological tests for brucellosis. He was referred to a specialized clinic with no recovery achievement after 5 months treatment. The musculoskeletal pain together with the patient’s occupation (animal husbandry), was resulted in a high clinical suspicion of brucellosis. Consequently, the patient underwent another serological test and Magnetic resonance imaging (MRI). He was diagnosed with brucellosis-induced spondylodiscitis by positive serology result and bone involvement on MRI. Regular treatment was then started, which led to clinical and radiological improvement at the end. With regard to chronic symptoms of the disease and despite the negative results of serological tests, it is recommended that radiological diagnostic methods such as MRI should be adopted in cases where there is a clinical suspicion of brucellosis.

scholarly journals Evaluating COVID-19 screening strategies based on serological tests

2020 ◽  
Author(s):  
Michela Baccini ◽  
Alessandra Mattei ◽  
Emilia Rocco ◽  
Giulia Vannucci ◽  
Fabrizia Mealli
Keyword(s):  
Reproduction Number ◽  
Serological Test ◽  
Screening Strategy ◽  
Antibody Detection ◽  
Screening Procedure ◽  
Rt Pcr ◽  
False Negatives ◽  
Serological Tests ◽  
Reliable Technique ◽  
Screening Strategies

ABSTRACTBackgroundFacing the SARS-CoV-2 epidemic requires intensive testing on the population to early identify and isolate infected subjects. Although RT-PCR is the most reliable technique to detect ongoing infections, serological tests are frequently proposed as tools in heterogeneous screening strategies. We analyze the performance of a screening strategy proposed in Tuscany (Italy), which first uses qualitative rapid tests for antibody detection, and then RT-PCR tests on the positive subjects.MethodsWe simulate the number of RT-PCR tests required by the screening strategy and the undetected ongoing infections in a pseudo-population of 500’000 subjects, under different prevalence scenarios and assuming a sensitivity of the serological test ranging from 0.50 to 0.80 (specificity=0.98). A compartmental model is used to predict the number of new infections generated by the false negatives two months after the screening, under different values of the infection reproduction number.ResultsAssuming a sensitivity equal to 0.80 and a prevalence of 0.3%, the screening procedure would require on average 11167.6 RT-PCR tests and would produce 300 false negatives, responsible after two months of a number of contagions ranging from 526 to 1132, under the optimistic scenario of a reproduction number between 0.5 to 1. Costs and false negatives increase with the prevalence.ConclusionsThe analyzed screening procedure should be avoided unless the prevalence and the rate of contagion are very low. The cost and effectiveness of the screening strategies should be evaluated in the actual context of the epidemic, accounting for the fact that it may change over time.

scholarly journals Serological diagnosis of Toxoplasma gondii: analysis of false-positive IgG results and implications

Parasite ◽  
2020 ◽  
Vol 27 ◽  
pp. 7 ◽  
Author(s):  
Loïc Simon ◽  
Judith Fillaux ◽  
Aurélie Guigon ◽  
Rose-Anne Lavergne ◽  
Odile Villard ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
False Positive ◽  
Primary Infection ◽  
Preventive Measures ◽  
Neospora Caninum ◽  
Confirmatory Test ◽  
Serological Tests ◽  
Past Infection ◽  
Recombinant Antigens ◽  
False Positivity

Background: Primary infection by Toxoplasma gondii in pregnant women can result in serious outcomes for the foetus. A false-positive IgG result during pregnancy can lead to a misdiagnosis of past infection and to stopping preventive measures. We collected 189 sera with positive Architect® Toxo IgG assay (Abbott Laboratories) and negative IgG results with at least two other serological tests, in order to find an explanation for the suspected false-positive IgG results. We used the recomLine Toxoplasma IgG® immunoblot (Mikrogen Diagnostik) to search for specific antigenic reactivities of the sera, and the LDBio Toxo II IgG® immunoblot (LDBio Diagnostics) as a confirmatory test. Results: The bands GRA8 and/or GRA7 were positive for 148 samples (78.3%). GRA8 was the most frequent band, appearing in 133 patterns (70.4%), whereas GRA7 was present for 49 samples (25.9%). Of the 81 samples tested with LDBio®, 23 (28.4%) turned out to be positive. Of the 58 negative LDBio® tests (71.6%) (real false-positive Architect® IgG), 23 samples (39.6%) did not show either a GRA8 or p30 band by recomLine®. Their false positivity with Architect® remains unexplained since Abbott uses these two recombinant antigens for their assay. Conclusions: The Architect® IgG false positivity for T. gondii seems to be due to reactivity against GRA8 for the majority of the sera and GRA7 to a lesser extent. The hypothesis of past contact with parasites genetically close to T. gondii such as Hammondia hammondi or Neospora caninum seems promising and should be assessed further.

scholarly journals A preliminary study on analytical performance of serological assay for SARS-CoV-2 IgM/IgG and application in clinical practice

2020 ◽  
Author(s):  
Quan Zhou ◽  
Danping Zhu ◽  
Huacheng Yan ◽  
Jingwen Quan ◽  
Zhenzhan Kuang ◽  
...  
Keyword(s):  
False Positive ◽  
Serological Test ◽  
Serum Antibody ◽  
False Positives ◽  
Antibody Detection ◽  
Immunochromatographic Assay ◽  
Response Analysis ◽  
Chemiluminescence Immunoassay ◽  
Asymptomatic Patients ◽  
Positive Rate

AbstractObjectiveTo investigate the performance of serological test and dynamics of serum antibody with the progress of SARS-CoV-2 infections.MethodsA total of 419 patients were enrolled including 19 confirmed cases and 400 patients from fever clinics. Their serial serum samples collected during the hospitalization were menstruated for IgM and IgG against SARS-CoV-2 using gold immunochromatographic assay and chemiluminescence immunoassay. We investigated whether thermal inactivation could affect the results of antibody detection. The dynamics of antibodies with the disease progress and false positive factors for antibody testing were also analyzed.ResultsThe positive rate of IgG detection was 91.67% and 83.33% using two CLIA, respectively. However, the IgM positive rate was dramatically declined might due to the lack of blood samples at early stages of the disease. The chemiluminescence immunoassay had a favorable but narrow linear range. Our work showed increased IgG values in serums from virus-negative patients and four negative samples were IgG weak-positive after thermal incubation. Our data showed the specificity of viral N+S proteins was higher than single antigen. Unlike generally thought that IgM appeared earlier than IgG, there is no certain chronological order of IgM and IgG seroconversion in COVID-19 patients. It was difficult to detect antibodies in asymptomatic patients suggesting that their low viral loads were not enough to cause immune response. Analysis of common interferent in three IgG false-positive patients, such as rheumatoid factor, proved that false positives were not caused by these interfering substances and antigenic cross-reaction.ConclusionsViral serological test is an effective means for SARS-CoV-2 infect detection using both chemiluminescence immunoassay and gold immunochromatographic assay. Chemiluminescence immunoassay against multi-antigens has obvious advantages but still need improve in reducing false positives.

scholarly journals COVID-19 and Dengue Combination Dilemma: A Case of Probable Dengue False Positivity in a COVID 19 Patient

2020 ◽  
pp. 133-135
Author(s):  
Mohammad Rafiqul Islam ◽  
Alamgir Hossan ◽  
MM Nasir Uddin ◽  
Md Tanvir Hasan
Keyword(s):  
Hypertensive Patient ◽  
False Positive ◽  
Rt Pcr ◽  
Positive Serology ◽  
False Positivity

A 58-year-old diabetic and hypertensive patient showed symptoms of fever for seven days with cough and irritation in throat for the same duration. He did not complain of any headache, shivering, confusion, breathlessness, tastelessness or smell abnormalities. His first RT-PCR for coronavirus disease 2019 (COVID-19) and IgM for dengue were both positive. His first PCV value and platelet value were normal on seventh and ninth day respectively. False positive serology for dengue may happen in COVID 19 cases. J Bangladesh Coll Phys Surg 2020; 38(0): 133-135

Are You Sure It's Syphilis? A Review of False Positive Serology

1995 ◽  
Vol 6 (4) ◽  
pp. 241-248 ◽  
Author(s):  
R Nandwani ◽  
D T P Evans
Keyword(s):  
Hiv Infection ◽  
False Positive ◽  
Positive Serology ◽  
Serological Tests ◽  
Aids Epidemic ◽  
False Positive Reactions ◽  
Syphilis Serology ◽  
Serodiagnosis Of Syphilis

Summary: This article on false positive serological reactions for syphilis reviews the rapid developments which have taken place in the serodiagnosis of syphilis in recent years since the advent of the AIDS epidemic. An overview of non-specific and specific treponemal serological tests in relation to acute and chronic biological false positive reactions is followed by closer consideration of syphilis serology in the context of HIV infection, pregnancy and other conditions which may produce false positive reactions.

scholarly journals Seropositivity to canine tick-borne pathogens in a population of sick dogs in Italy

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Jairo Alfonso Mendoza-Roldan ◽  
Giovanni Benelli ◽  
Marcos Antonio Bezerra-Santos ◽  
Viet-Linh Nguyen ◽  
Giuseppe Conte ◽  
...  
Keyword(s):  
Borrelia Burgdorferi ◽  
Serological Test ◽  
Control Strategies ◽  
Central Italy ◽  
Rickettsia Conorii ◽  
High Seroprevalence ◽  
The South ◽  
Serum Samples ◽  
Serological Tests ◽  
Distribution Maps

Abstract Background Canine vector-borne diseases (CVBDs) associated to ticks are among the most important health issues affecting dogs. In Italy, Ehrlichia canis, Anaplasma spp., Rickettsia conorii and Borrelia burgdorferi (s.l.) have been studied in both healthy canine populations and those clinically ill with suspected CVBDs. However, little information is currently available on the overall prevalence and distribution of these pathogens in the country. The aim of this study was to assess the prevalence and distribution of tick-borne pathogens (TBPs) in clinically suspect dogs from three Italian macro areas during a 15-year period (2006–2020). Methods A large dataset (n = 21,992) of serological test results for selected TBPs in three macro areas in Italy was analysed using a Chi-square test to evaluate the associations between the categorical factors (i.e. macro area, region, year, sex and age) and a standard logistic regression model (significance set at P = 0.05). Serological data were presented as annual and cumulative prevalence, and distribution maps of cumulative positive cases for TBPs were generated. Results Of the tested serum samples, 86.9% originated from northern (43.9%) and central (43%) Italy. The majority of the tests was requested for the diagnosis of E. canis (47%; n = 10,334), followed by Rickettsia spp. (35.1%; n = 7725), B. burgdorferi (s.l.) (11.6%; n = 2560) and Anaplasma spp. (6.2%; n = 1373). The highest serological exposure was recorded for B. burgdorferi (s.l.) (83.5%), followed by Rickettsia spp. (64.9%), Anaplasma spp. (39.8%) and E. canis (28.7%). The highest number of cumulative cases of Borrelia burgdorferi (s.l.) was recorded in samples from Tuscany, central Italy. Rickettsia spp. was more prevalent in the south and on the islands, particularly in dogs on Sicily older than 6 years, whereas Anaplasma spp. was more prevalent in the north and E. canis more prevalent in the south and on the islands. Conclusions The results of this study highlight the high seroprevalence and wide distribution of the four TBPs in dogs with clinically suspected CVBDs from the studied regions of Italy. The very high seroprevalence of B. burgdorferi (s.l.) exemplifies a limitation of this study, given the use of clinically suspect dogs and the possibility of cross-reactions when using serological tests. The present research provides updated and illustrative information on the seroprevalence and distribution of four key TBPs, and advocates for integrative control strategies for their prevention. Grapic abstract

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