scholarly journals The sensitivity, specificity and efficiency values of some serological tests used in the diagnosis of paracoccidioidomycosis

1991 ◽  
Vol 33 (4) ◽  
pp. 277-280 ◽  
Author(s):  
Gilda M.B. Del Negro ◽  
Nilma M. Garcia ◽  
Elaine G. Rodrigues ◽  
M. Isabel N. Cano ◽  
Mônica S.M.V. de Aguiar ◽  
...  
Keyword(s):  
Yeast Cell ◽  
Culture Filtrate ◽  
Blood Donors ◽  
Complement Fixation ◽  
Paracoccidioides Brasiliensis ◽  
Yeast Culture ◽  
Double Immunodiffusion ◽  
Serological Tests ◽  
Sensitivity Specificity ◽  
Negative Controls

This work reports on the results of double immunodiffusion (ID), counterimmunoelectrophoresis (CIE), complement fixation (CF) and indirect immunofluorescence (IIF) techniques in the serodiagnosis of paracoccidioidomycosis. The study was undertaken on four groups of individuals: 46 patients with untreated paracoccidioidomycosis, 22 patients with other deep mycoses, 30 with other infectious diseases (tuberculosis and cutaneous leishmaniasis) and 47 blood donors as negative controls. Data were obtained using Paracoccidioides brasiliensis antigens, i.e.,a yeast culture filtrate for ID, CIE and CF, and a yeast cell suspension for IIF. The sensitivity, specificity and efficiency values were measured according to GALEN & GAMBINO8.The gel precipitation tests (ID and CIE) showed the greatest sensitivity (91.3 and 95.6%, respectively), maximum specificity (100%) and the highest efficiency values when compared to the CF and IIF tests.

scholarly journals Serological Diagnosis of Paracoccidioidomycosis through a Western Blot Technique

2012 ◽  
Vol 19 (4) ◽  
pp. 616-619 ◽  
Author(s):  
M. C. Z. Perenha-Viana ◽  
I. A. A. Gonzales ◽  
S. R. Brockelt ◽  
L. N. C. Machado ◽  
T. I. E. Svidzinski
Keyword(s):  
Western Blot ◽  
Positive Reaction ◽  
Paracoccidioides Brasiliensis ◽  
Double Immunodiffusion ◽  
Serological Tests ◽  
Content Type ◽  
Mycological Examination ◽  
Low Sensitivity ◽  
Effective Diagnosis ◽  
Negative Controls

ABSTRACTParacoccidioidomycosis (PCM) is a serious infectious disease that progresses toward death if untreated. Its confirmatory diagnosis is made by the detection of the fungusParacoccidioides brasiliensisin a direct mycological examination or by histopathology. However, these techniques are of low sensitivity. Serological tests seem to be more promising. The objective of this study was to test Western blot (WB) analysis using sera from patients suspected of PCM to determine whether it represents a safe and sensitive serological technique for a rapid and effective diagnosis for this disease. Sera from 517 patients were analyzed through WB analysis and double-immunodiffusion (DID) techniques using a crude exoantigen ofP. brasiliensis339. DID gave positive reactions for 140 sera (27%) and WB for 250 sera (48.4%). All sera that had a positive reaction by DID also had a positive result with a 43-kDa glycoprotein by WB analysis. Among the 377 samples that were negative by DID, 29.1% were reactive in WB analysis. For the cutoff dilution used (1:400), a positive reaction was not observed with any of the 102 sera from patients with other diseases in regions where such diseases are endemic and 30 healthy individuals tested as negative controls. These results prove WB analysis to be a sensitive technique and suggest its inclusion among routine laboratory assays as a safe method for PCM diagnosis.

scholarly journals Serodiagnosis of Anthroponotic Cutaneous Leishmaniasis (ACL) Caused by Leishmania tropica in Sanliurfa Province, Turkey, Where ACL Is Highly Endemic

2007 ◽  
Vol 14 (11) ◽  
pp. 1409-1415 ◽  
Author(s):  
Fadile Yildiz Zeyrek ◽  
Metin Korkmaz ◽  
Yusuf Özbel
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Western Blotting ◽  
Blood Donors ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Serological Tests ◽  
Western Blot Test ◽  
Conventional Elisa ◽  
Negative Controls ◽  
Positive Controls

ABSTRACT In this study, we aimed to evaluate the validity of the conventional enzyme-linked immunosorbent assay (ELISA) and the Western blotting test for the diagnosis of anthroponotic cutaneous leishmaniasis (ACL) using serum samples obtained from 51 patients with parasitologically proven nontreated CL (NonT-CL patients) and 62 patients under treatment for CL (UT-CL patients). Additionally, 29 serum samples obtained from patients with parasitologically and serologically proven visceral leishmaniasis (VL) were also used as positive controls, and serum samples from 43 blood donors were used as negative controls. All sera were diluted to the same dilution (1/100). Leishmania infantum MON-1 was used as the antigen in the conventional ELISA. The sera of 27 (93.1%) of 29 VL patients were seropositive by ELISA, while the sera of 40 (78.4%) of 51 NonT-CL patients and 43 (69.3%) of 62 UT-CL patients were seropositive by the conventional ELISA. The absorbance values of the CL patients' sera were significantly lower than the absorbance values of the VL patients' sera. Bands between 15 and 118 kDa were detected in two groups of CL patients. Among all bands, the 63-kDa band was found to be more sensitive (88.5%). When we evaluated the Western blotting results for the presence of at least one of the diagnostic antigenic bands, the sensitivity was calculated to be 99.1%. By using serological tests, a measurable antibody response was detected in most of the CL patients in Sanliurfa, Turkey. It is also noted that this response can be changed according to the sizes, types, and numbers of lesions that the patient has. The Western blot test was found to be more sensitive and valid than the conventional ELISA for the serodiagnosis of ACL. In some instances, when it is very difficult to demonstrate the presence of parasites in the smears, immunodiagnosis can be a valuable alternative for the diagnosis of ACL.

Validity of a Serological Diagnostic Kit for SARS-CoV-2 Available in Iran

2020 ◽  
Vol 23 (9) ◽  
pp. 629-632
Author(s):  
Hamid Reza Shamsollahi ◽  
Mostafa Amini ◽  
Shaban Alizadeh ◽  
Saharnaz Nedjat ◽  
Ali Akbari-Sari ◽  
...  
Keyword(s):  
Diagnostic Techniques ◽  
Effective Control ◽  
Molecular Technique ◽  
Size Estimation ◽  
Medical Sciences ◽  
Serological Tests ◽  
Standard Case ◽  
Epidemic Size ◽  
Low Sensitivity ◽  
Negative Controls

Background: The Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic broke out in December 2019 and is now characterized as a pandemic. Effective control of this infectious disease requires access to diagnostic techniques, for both case finding and epidemic size estimation. The molecular technique is routinely used worldwide. Although it is the "standard" case detection and management method, it has its own shortcomings. Thus, some easy-to-use rapid serological tests have been developed. Methods: One hundred and fourteen positive RT-PCR-diagnosed patients were tested by VivaDiag Kit, a brand of rapid serological kits available in hospitals affiliated to Tehran University of Medical Sciences (TUMS), Tehran, Iran. Frozen serum specimens taken from healthy people in summer and fall 2019 were also tested as negative controls. Results: Test sensitivity was 47.9% (95% confidence interval [CI]: 38.8-56.9) for IgM and 47.0% (95% CI: 38.0–56.0) for IgG. There was no difference between IgG and IgM seropositivity except in one case. Specificity was calculated as 99.0% (95% CI: 96.4–99.9) for IgM and of 100.0% (95% CI: 0.98.2–100.0) for IgG. Sensitivity was higher in men and older participants. Conclusion: This test can be used for epidemiological investigations, especially for the estimation of the level of infection in the community, after it is properly corrected for sensitivity and specificity. The low sensitivity could be attributed to the technical limitations of the kit or low levels of antibodies after infection. The different sensitivity in age and sex groups supports the hypothesis that different people show different immune responses to this virus.

scholarly journals COVID-19 Seroprevalence among Healthcare Workers of a Large COVID-19 Hospital in Rome Reveals Strengths and Limits of Two Different Serological Tests

2021 ◽  
Vol 18 (5) ◽  
pp. 2650
Author(s):  
Giuseppe Vetrugno ◽  
Daniele Ignazio La Milia ◽  
Floriana D’Ambrosio ◽  
Marcello Di Pumpo ◽  
Roberta Pastorino ◽  
...  
Keyword(s):  
Blood Test ◽  
Healthcare Workers ◽  
Point Of Care ◽  
Venous Blood ◽  
Administrative Staff ◽  
Serological Tests ◽  
Predictive Values ◽  
Work From Home ◽  
Significant Difference ◽  
Sensitivity Specificity

Healthcare workers are at the forefront against COVID-19, worldwide. Since Fondazione Policlinico Universitario A. Gemelli (FPG) IRCCS was enlisted as a COVID-19 hospital, the healthcare workers deployed to COVID-19 wards were separated from those with limited/no exposure, whereas the administrative staff were designated to work from home. Between 4 June and 3 July 2020, an investigation was conducted to evaluate the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin (IgG) antibodies among the employees of the FPG using point-of-care (POC) and venous blood tests. Sensitivity, specificity, and predictive values were determined with reverse-transcription polymerase chain reaction on nasal/oropharyngeal swabs as the diagnostic gold standard. The participants enrolled amounted to 4777. Seroprevalence was 3.66% using the POC test and 1.19% using the venous blood test, with a significant difference (p < 0.05). The POC test sensitivity and specificity were, respectively, 63.64% (95% confidence interval (CI): 62.20% to 65.04%) and 96.64% (95% CI: 96.05% to 97.13%), while those of the venous blood test were, respectively, 78.79% (95% CI: 77.58% to 79.94%) and 99.36% (95% CI: 99.07% to 99.55%). Among the low-risk populations, the POC test’s predictive values were 58.33% (positive) and 98.23% (negative), whereas those of the venous blood test were 92.86% (positive) and 98.53% (negative). According to our study, these serological tests cannot be a valid alternative to diagnose COVID-19 infection in progress.

scholarly journals A High-Performance Multiplex Immunoassay for Serodiagnosis of Flavivirus-Associated Neurological Diseases in Horses

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Cécile Beck ◽  
Philippe Desprès ◽  
Sylvie Paulous ◽  
Jessica Vanhomwegen ◽  
Steeve Lowenski ◽  
...  
Keyword(s):  
High Performance ◽  
Neurological Diseases ◽  
Expression System ◽  
Cross Reactivity ◽  
Encephalitis Virus ◽  
Serological Tests ◽  
Multiplex Immunoassay ◽  
Tick Borne Encephalitis ◽  
Tick Borne Encephalitis Virus ◽  
Negative Controls

West Nile virus (WNV), Japanese encephalitis virus (JEV), and tick-borne encephalitis virus (TBEV) are flaviviruses responsible for severe neuroinvasive infections in humans and horses. The confirmation of flavivirus infections is mostly based on rapid serological tests such as enzyme-linked immunosorbent assays (ELISAs). These tests suffer from poor specificity, mainly due to antigenic cross-reactivity among flavivirus members. Robust diagnosis therefore needs to be validated through virus neutralisation tests (VNTs) which are time-consuming and require BSL3 facilities. The flavivirus envelope (E) glycoprotein ectodomain is composed of three domains (D) named DI, DII, and DIII, with EDIII containing virus-specific epitopes. In order to improve the serological differentiation of flavivirus infections, the recombinant soluble ectodomain of WNV E (WNV.sE) and EDIIIs (rEDIIIs) of WNV, JEV, and TBEV were synthesised using theDrosophilaS2 expression system. Purified antigens were covalently bonded to fluorescent beads. The microspheres coupled to WNV.sE or rEDIIIs were assayed with about 300 equine immune sera from natural and experimental flavivirus infections and 172 nonimmune equine sera as negative controls. rEDIII-coupled microspheres captured specific antibodies against WNV, TBEV, or JEV in positive horse sera. This innovative multiplex immunoassay is a powerful alternative to ELISAs and VNTs for veterinary diagnosis of flavivirus-related diseases.

scholarly journals Serological tests for the detection of antibodies to Mycoplasma gallisepticum in chickens and turkeys

1968 ◽  
Vol 66 (2) ◽  
pp. 249-267 ◽  
Author(s):  
F. T. W. Jordan ◽  
P. Kulasegaram
Keyword(s):  
Positive Reaction ◽  
Complement Fixation ◽  
Haemagglutination Inhibition ◽  
Mycoplasma Gallisepticum ◽  
Metabolic Inhibition ◽  
Agar Gel ◽  
Serological Tests ◽  
Anamnestic Response ◽  
Initial Infection ◽  
Gel Method

SUMMARYA comparison was undertaken of several serological tests in determining the response of chickens and turkeys experimentally infected with the A 514 strain of Mycoplasma gallisepticum.After a single intratracheal inoculation of chickens with a culture of the organism, the highest titres were obtained by the indirect complement fixation (ICF) test, followed by the tube agglutination (TA), haemagglutination inhibition (HI), slide agglutination (SA) and metabolic inhibition (MI) tests. By all these tests positive titres were observed within the first week and peak titres between the first and second weeks. At 5 months there was no positive reaction by the ICF test but most chickens gave positive readings by the TA, HI and SA tests for at least 14 months after infection, but turkey sera became negative by all tests after 3 months.A disadvantage of the ICF test was that sera up to a dilution of 1/8 and 1/16 for chicken and turkey respectively were anticomplementary, and in turkeys this masked the ICF titre, which presumably was low following one intratracheal inoculation. Titres in turkeys with the TA, HI and SA tests followed the pattern seen with chickens and were generally lower than those found by other workers probably because of the avirulent nature of the inoculum used.The WB test was the least sensitive of the agglutination tests but is useful as a flock test which can be undertaken on the farm.The MI test gave the lowest titres of all and antibodies could be detected for only 4 months following one intratracheal inoculation. Even with serum prepared by multiple inoculations in chickens the titre was never higher than 1/32 compared with 1/1024 for serum similarly prepared in rabbits.Precipitins were detected by the agar gel method in the sera of chickens and turkeys after two intratracheal inoculations but in only some of the chickens and none of the turkeys after one inoculation.By all tests higher titres were observed with chicken than turkey sera and antibodies persisted for a longer time.Re-infection of chickens when antibodies to the initial infection had become low, and of turkeys when antibodies were no longer detectable, gave rise to an anamnestic response with titres which were higher than before.Antiserum to M. gallisepticum prepared in chickens is comparable with that prepared in rabbits except for low titres by the MI test.

scholarly journals Atypical disseminated cutaneous histoplasmosis in an immunocompetent child, caused by an "aberrant" variant of Histoplasma capsulatum var. capsulatum

1999 ◽  
Vol 41 (3) ◽  
pp. 195-202 ◽  
Author(s):  
Carlos da Silva LACAZ ◽  
Gilda Maria Barbaro DEL NEGRO ◽  
Mônica Scarpelli Martinelli VIDAL ◽  
Elisabeth Maria HEINS-VACCARI ◽  
Roseli Freitas dos SANTOS ◽  
...  
Keyword(s):  
Histoplasma Capsulatum ◽  
Complement Fixation ◽  
Double Immunodiffusion ◽  
Granulomatous Reaction ◽  
Cutaneous Lesions ◽  
Biopsy Material ◽  
Specific Staining ◽  
Hyperimmune Serum ◽  
Circulating Antigen ◽  
Immunoenzymatic Assay

A case of atypical disseminated cutaneous histoplasmosis in a five-year old, otherwise healthy child, native and resident in São Paulo metropolitan area is reported. Cutaneous lesions were clinically atypical. Histologic examination disclosed a granulomatous reaction but no fungal structures could be demonstrated by specific staining nor by immunohistochemical reaction. The fungus was isolated from biopsy material on two different occasions, confirming diagnosis of an unusual fungal infection. The fungus, originally thought to be a Sepedonium sp. due to the large sized, hyaline or brownish colored tuberculated macroconidia and to lack of dimorphism (yeast form at 37 °C) produce H and M antigens, visualized by the immunodiffusion with rabbit anti-Histoplasma capsulatum hyperimmune serum. Patient’s serum sample was non reactive with H. capsulatum antigen by immunodiffusion, counterimmunoelectrophoresis and complement fixation tests, and immunoenzymatic assay failed to detect the specific circulating antigen. This serum was tested negative by double immunodiffusion when antigen obtained from one of the isolated samples was used. Both cultures were sent to Dr. Leo Kaufman, Ph.D. (Mycoses Immunodiagnostic Laboratory, CDC-Atlanta/USA), who identified them as H. capsulatum by the exoantigen and gen-probe tests. Both clinic and mycologic characteristics of the present case were atypical, suggesting the fungus isolated is an “aberrant variant” of H. capsulatum var. capsulatum, as described by SUTTON et al. in 199719. Treatment with itraconazole 100 mg/day led to cure within 90 days

scholarly journals A quantitative comparison of the sensitivity of serological tests for bovine brucellosis to different antibody classes

1976 ◽  
Vol 76 (2) ◽  
pp. 287-298 ◽  
Author(s):  
G. S. Allan ◽  
R. J. Chappel ◽  
P. Williamson ◽  
D. J. McNaught
Keyword(s):  
Complement Fixation Test ◽  
Complement Fixation ◽  
Quantitative Comparison ◽  
Agglutination Test ◽  
Bovine Brucellosis ◽  
Serological Tests ◽  
Plate Test ◽  
Specific Antibodies ◽  
The Rose ◽  
Serum Agglutination

SUMMARYBrucella-specific antibodies of different immunoglobulin classes were quantitatively evaluated with respect to their efficiency in serological tests for bovine brucellosis.IgM reacted more efficiently than IgG1and IgG2in both the Rose Bengal plate test and serum agglutination test. The complement fixation test was found to be slightly more sensitive to IgM than to IgG1and did not react to IgG2.IgM was, however, partly inactivated when heated at 60°C. in the presence of serum.

Evaluation of diagnostic accuracy of 10 serological assays for detection of SARS-CoV-2 antibodies.

2020 ◽  
Author(s):  
MD. ◽  
Sara Gómez de Frutos ◽  
Diego Domingo García PharmD ◽  
Eva Navarro Lara ◽  
Ayla Yarci Carrión ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Gold Standard ◽  
Epidemiological Studies ◽  
Antibody Detection ◽  
Diagnostic Tools ◽  
Sensitivity Range ◽  
Sensitivity Specificity ◽  
Negative Controls ◽  
Ig G ◽  
Positive Controls

Abstract BackgroundAntibody detection is essential to establish exposure, infection and immunity to SARS-CoV-2, as well as to perform epidemiological studies. The worlwide urge for new diagnostic tools to control the pandemic has led to a quick in- corporation in clinical practice of the recently developed serological assays.MethodsWe evaluated the diagnostic accuracy to detect Ig G, Ig M+A and/or IgA anti SARS-CoV-2 of 10 different assays: 3 Lateral Flow card inmunoassays, 4 en- zyme-linked inmunoabsorbent assay (ELISA) and 3 chemiluminescent particle immunoassays (CMIA). Using PCR for COVID-19 as gold standard, sensitivity, specificity, PPV, and NPV were determined. Each assay was tested in 2 groups: Positive Controls, formed by 50 sera from 50 patients with SARS-CoV-2 pneu- monia with positive PCR; Negative Controls, formed by 50 sera from 50 pa- tients with respiratory infection non-COVID-19.ResultsSensitivity range of the 10 assays evaluated for patients with positive COVID-19 PCR was 40-77% (65-81% considering IgG plus IgM). Specificity ranged 83-100%. VPP and VPN were respectively 81-100% and 61.6-81%.ConclusionsResults obtained varied widely among the assays evaluated.Highest diagnostic accuracy was obtained with ELISA and CMIAs, but they last much longer.

scholarly journals Model Proficiency Testing Scheme for Serological Diagnosis of Brucellosis: Interlaboratory Study

2004 ◽  
Vol 87 (4) ◽  
pp. 965-971 ◽  
Author(s):  
Donatella Nannini ◽  
Manuela Tittarelli ◽  
Lucilla Ricci ◽  
Annamaria Conte ◽  
Bernardo Di Emidio ◽  
...  
Keyword(s):  
Complement Fixation Test ◽  
Complement Fixation ◽  
Fixation Test ◽  
Reference Laboratory ◽  
Correct Result ◽  
The European Union ◽  
Serological Tests ◽  
Testing Scheme ◽  
Z Scores ◽  
Qualitative Test

Abstract A model interlaboratory testing scheme was developed by the Italian National Reference Laboratory for Brucellosis. This scheme was planned for both qualitative (Rose Bengal Plate Test; RBPT) and quantitative (Complement Fixation Test; CFT) serological tests and involved a total of 42 laboratories. In the preparation of this scheme, reference was made to general protocols and guidelines and to methods reported in the literature, which were applicable to analytical chemistry laboratories. Six field sera from naturally infected animals, one positive serum at a titer below the European Union (EU) positivity threshold, and 5 sera positive at titers between 20 and 851 International Units of Complement Fixation Test (IUCFT)/mL plus one negative serum were used to produce a panel of test sera. To evaluate laboratory performances in the quantitative test for each tested sample examined, z-scores based on robust summary statistics (the median and normalized interquartile range) were used. To evaluate overall laboratory performance, 2 types of combined z-scores were used: Rescaled Sum of Scores and Sum of Squared Scores. In the case of the qualitative test (RBPT), results were analyzed by a Bayesian approach. A Beta distribution, based on the result of each laboratory, was calculated and used to estimate the probability of each laboratory giving a correct result and its uncertainty.

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