scholarly journals Assessment of serological tests for antibodies to different antigens of the SARS-CoV-2 virus: comparison of six immunoassays

2021 ◽  
Vol 23 (6) ◽  
pp. 1395-1404
Author(s):  
V. V. Belyakova ◽  
O. A. Maiorova ◽  
N, V. Ivanova ◽  
I. E. Stepanova ◽  
M. A. Smerdova ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Rapid Test ◽  
Diagnostic Methods ◽  
Federal State ◽  
Control Group ◽  
Laboratory Diagnostics ◽  
Igg Antibodies ◽  
Diagnostic Systems ◽  
Serum Samples ◽  
Serological Tests

The new coronavirus SARS-CoV-2 has become a global challenge to medicine and, in particular, laboratory diagnostics. The study of the antibodies’ level to SARS-CoV-2 can be used as a confirmation test in the diagnosis of a disease, but it becomes of paramount importance in assessing population immunity resulting from a disease or vaccination, as well as in selection of convalescent plasma donors. The kits developed in our country and abroad for detecting antibodies to the SARS-CoV-2 virus differ both in the methods of testing and in the used coronavirus antigens to which the antibodies are directed. The aim of this study was to compare the diagnostic sensitivity and specificity of five kits for the detection of IgG antibodies to the SARS-CoV-2 virus, based on different diagnostic methods. Serum samples from 137 COVID-19 convalescents and 166 donors of blood and its components were examined. The control group consisted of 50 blood sera collected at the beginning of 2019 and 19 sera collected in 2018 (before the advent of the SARS-CoV-2 virus) and stored at -70 °C. Testing was carried out in analytical systems: rapid test “COVID-19 IgM/IgG Rapid Test (Colloidal Gold)” (China), on an automatic immunochemical analyzer Abbott Architect™ i2000 and kit “SARS-CoV2-IgG” (Abbot, Chicago , IL USA), by the chemiluminescence method using an automatic analyzer of the CL series and kits of the “Mindray” company (China) “SARS-CoV-2 IgM” and “SARS-CoV-2 IgG” and by the enzyme immunoassay method on the kits of the companies “Diagnostic Systems” Ltd (Russia, Nizhny Novgorod) “DS-IFA-ANTI-SARS-CoV-2-G”, “Xema” Ltd (Federal State Budgetary Institution “National Medical Research Center of Hematology” of the Ministry of Health of Russia) “SARS-CoV-2-IgG-IFA” and “Vector-Best” CJSC (Russia, Novosibirsk)” SARS-COV-2-IgM-IFA-BEST” and “SARS-COV-2-IgG-IFABEST”. When comparing the results of testing 137 plasma samples on the Vector-Best and Mindray kits for IgG antibodies, 127 samples were positive, 7 samples were negative on both kits, the discrepancy was 2.2%. In the study of IgM antibodies, 32.1% were positive, and 52.6% were negative in both kits. The discrepancy rate was 15.3%. Out of 166 samples, 1 serum (0.6%) was negative in 5 kits. On the Mindray kit, IgG antibodies to the antigens of the SARS-CoV-2 virus were detected in 165 samples (99.4%), on Vector-Best – in 164 sera (98.8%), on Diagnostic systems – in 151 (90.96%), on Xema – in 154 (92.8%), and on Abbott – in 155 samples (93.4%). At the same time, 135 (81.33%) samples were positive in all kits, while 30 samples had discordant results (18.07%), and in 9 sera, specific IgG was not detected in 2 or more kits. ROC analysis revealed a high diagnostic value of all tested kits (AUC from 0.908 to 0.998), which indicates a high quality of the separation model of positive and negative samples (p < 0.001). With the cut-off set by the manufacturers, the sensitivity and specificity ranged from 82.8% and 93.3% for the Diagnostic Systems kit to 99.4% and 95.8% for the VectorBest kit. The calculated correlation coefficients were higher between kits with a similar composition of the antigen used in the kits; therefore, it is better to monitor the dynamics of antibodies by diagnostic kits from the same manufacturer.

scholarly journals Evaluation of the performance of three serological tests for diagnosis of Leishmania infantum infection in dogs using latent class analysis

2020 ◽  
Vol 29 (4) ◽  
Author(s):  
Asier Basurco ◽  
Alda Natale ◽  
Katia Capello ◽  
Antonio Fernández ◽  
María Teresa Verde ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Leishmania Infantum ◽  
Latent Class ◽  
Rapid Test ◽  
Antibody Test ◽  
Latent Class Models ◽  
Canine Leishmaniasis ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Serological Tests

Abstract Canine leishmaniasis (CanL) is a disease caused by Leishmania infantum. Serological methods are the most common diagnostic techniques used for the diagnosis of the CanL. The objective of our study was to estimate the sensitivity and specificity of one in-house ELISA kit (ELISA UNIZAR) and three commercially available serological tests (MEGACOR Diagnostik GmbH) including an immunochromatographic rapid test (FASTest LEISH®), an immunofluorescent antibody test (MegaFLUO LEISH®) and an enzyme-linked immunosorbent assay (MegaELISA LEISH®), using latent class models in a Bayesian analysis. Two hundred fifteen serum samples were included. The highest sensitivity was achieved for FASTest LEISH® (99.38%), ELISA UNIZAR (99.37%), MegaFLUO LEISH® (99.36%) followed by MegaELISA LEISH® (98.49%). The best specificity was obtained by FASTest LEISH® (98.43%), followed by ELISA UNIZAR (97.50%), whilst MegaFLUO LEISH® and MegaELISA LEISH® obtained the lower specificity (91.94% and 91.93%, respectively). The results of present study indicate that the immunochromatographic rapid test evaluated FASTest LEISH® show similar levels of sensitivity and specificity to the quantitative commercial tests. Among quantitative serological tests, sensitivity and specificity were similar considering ELISA or IFAT techniques.

scholarly journals Rapid Serological Tests for SARS-COV-2: Diagnostic Performance of Four Commercial Assays

2020 ◽  
Author(s):  
Sérgio Monteiro de Almeida ◽  
Regiane Nogueira Spalanzani ◽  
Meri Bordignon Nogueira ◽  
Beatriz Sanada Spiri ◽  
Barbara Maria Cavalli ◽  
...  
Keyword(s):  
Diagnostic Performance ◽  
Rapid Test ◽  
Nucleic Acid Amplification ◽  
Control Group ◽  
Serum Samples ◽  
Serological Tests ◽  
Test Kit ◽  
Healthy Control ◽  
One Step ◽  
Substantial Heterogeneity

Abstract Background. This study aimed to assess the diagnostic performance of lateral flow immunochromatographic assays (LFA) of four different manufacturers to identify SARS-CoV-2 antibodies (IgM, IgG or total), comparing them with the nucleic acid amplification test (NAAT) or clinical defined (definite or probable SARS-CoV-2 infection respectively). Methods. 119 serum samples were randomly selected by convenience and distributed in the groups: (1) Group with SARS-CoV-2 infection [n=82; RT-qPCR positive (definite, n=70), and probable (n=12)]; (2) other diseases [n= 27; other viruses identified (n=8), SARS of other etiologies (n=19)]; (3) healthy control group (n=10). LFA essays of four manufacturers were compared: MedTest Coronavírus (COVID-19) IgG/IgM (MedLevensohn, Brazil); COVID-19 IgG/IgM ECO Test (Ecodiagnóstica, Brazil); Camtech COVID-19 IgM/IgG Rapid Test Kit (Camtech Diagnostics Pte Ltd, Singapore); and one Step COVID-19 Test for total antibodies (Guangzhou Wondfo Biotech Co, China).Results. The four tests studied showed high diagnostic performance characteristics for the diagnoses of definite or probable SARS-CoV-2 infection. The best measures were for the Wondfo test: sensitivity (86.59%; 95%CI, 77.26-93.11%); specificity (100%; 90.51-100%); DOR (257; 60-1008); LR+ (33.43; 4.82-231.85); LR− (0.13; 0.08 - 0.23); accuracy (90.76%; 84.06- 95.29%); Matthews Correlation coefficient (MCC) 0.82. Although considering only the probable SARS-CoV-2 infection (PCR-) cases, all the kits studied showed limited values.Conclusion. Our data demonstrate the excellent performance of LFA for the diagnoses of definite or probable SARS-CoV-2 infection. There was substantial heterogeneity in sensitivities of IgM and IgG antibodies among the manufacturers. LFA tests cannot replace molecular diagnostics, but should be used as additional screening tool.

scholarly journals Rapid Serological Tests for SARS-COV-2: Diagnostic Performance of Four Commercial Assays

2020 ◽  
Author(s):  
Sérgio Monteiro de Almeida ◽  
Regiane Nogueira Spalanzani ◽  
Meri Bordignon Nogueira ◽  
Beatriz Sanada Spiri ◽  
Barbara Maria Cavalli ◽  
...  
Keyword(s):  
Diagnostic Performance ◽  
Rapid Test ◽  
Nucleic Acid Amplification ◽  
Control Group ◽  
Serum Samples ◽  
Serological Tests ◽  
Test Kit ◽  
Healthy Control ◽  
One Step ◽  
Substantial Heterogeneity

Abstract Background. This study aimed to assess the diagnostic performance of lateral flow immunochromatographic assays (LFA) of four different manufacturers to identify SARS-CoV-2 antibodies (IgM, IgG or total), comparing them with the nucleic acid amplification test (NAAT) or clinical defined (definite or probable SARS-CoV-2 infection respectively). Methods. 119 serum samples were randomly selected by convenience and distributed in the groups: (1) Group with SARS-CoV-2 infection [n=82; RT-qPCR positive (definite, n=70), and probable (n=12)]; (2) other diseases [n= 27; other viruses identified (n=8), SARS of other etiologies (n=19)]; (3) healthy control group (n=10). LFA essays of four manufacturers were compared: MedTest Coronavírus (COVID-19) IgG/IgM (MedLevensohn, Brazil); COVID-19 IgG/IgM ECO Test (Ecodiagnóstica, Brazil); Camtech COVID-19 IgM/IgG Rapid Test Kit (Camtech Diagnostics Pte Ltd, Singapore); and one Step COVID-19 Test for total antibodies (Guangzhou Wondfo Biotech Co, China).Results. The four tests studied showed high diagnostic performance characteristics for the diagnoses of definite or probable SARS-CoV-2 infection. The best measures were for the Wondfo test: sensitivity (86.59%; 95%CI, 77.26-93.11%); specificity (100%; 90.51-100%); DOR (257; 60-1008); LR+ (33.43; 4.82-231.85); LR− (0.13; 0.08 - 0.23); accuracy (90.76%; 84.06- 95.29%); Matthews Correlation coefficient (MCC) 0.82. Although considering only the probable SARS-CoV-2 infection (PCR-) cases, all the kits studied showed limited values.Conclusion. Our data demonstrate the excellent performance of LFA for the diagnoses of definite or probable SARS-CoV-2 infection. There was substantial heterogeneity in sensitivities of IgM and IgG antibodies among the manufacturers. LFA tests cannot replace molecular diagnostics, but should be used as additional screening tool.

scholarly journals Detection of Anti-LipL32 Antibodies in Serum Samples from Horses with Chronic Intraocular Infection with Leptospira spp.

Pathogens ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1325
Author(s):  
Tobias Geiger ◽  
Hartmut Gerhards ◽  
Bettina Wollanke
Keyword(s):  
Sensitivity And Specificity ◽  
Aqueous Humor ◽  
Screening Method ◽  
Rapid Test ◽  
High Sensitivity ◽  
Agglutination Test ◽  
Laboratory Diagnostics ◽  
Surgical Removal ◽  
Serum Samples ◽  
Equine Recurrent Uveitis

Equine recurrent uveitis (ERU) is typically caused by chronic intraocular leptospiral infection in warm-blooded horses in central Europe. The most effective therapy for leptospiral-induced ERU is the surgical removal of diseased vitreous (vitrectomy). Since vitrectomy is a highly specialized and invasive surgery, the indication must be determined very carefully. In order to obtain evidence of intraocular leptospiral infection by laboratory diagnostics in questionable leptospiral ERU-cases, sampling of aqueous humor is required, because serum tests using microscopic agglutination test (MAT) are too unspecific. The SNAP Lepto is a cross-species rapid test for the detection of anti-Lipl32 antibodies that has a high sensitivity (0.97) and specificity (1.00) for the detection of anti-leptospiral antibodies using aqueous humor or vitreous samples, which is comparable to MAT. To evaluate sensitivity and specificity of SNAP Lepto using serum, serum samples from 90 horses with confirmed leptospiral ERU and from 103 ocularly healthy horses were tested by both MAT and SNAP Lepto. Sensitivity was similar for both tests (0.82 vs. 0.79), but specificity was lower for MAT (0.52 vs. 0.95). Sensitivity and specificity are therefore lower in serum samples compared to intraocular samples, however, the SNAP Lepto is far superior to MAT and suitable as a screening method using equine serum.

scholarly journals Rapid Serological Tests for Sars-Cov-2: Diagnostic Performance of Four Commercial Assays

2021 ◽  
Author(s):  
Sérgio Monteiro de Almeida ◽  
Regiane Nogueira Spalanzani ◽  
Meri Bordignon Nogueira ◽  
Beatriz Sanada ◽  
Barbara Maria Cavalli ◽  
...  
Keyword(s):  
Diagnostic Performance ◽  
Rapid Test ◽  
Nucleic Acid Amplification ◽  
Control Group ◽  
Serum Samples ◽  
Serological Tests ◽  
Test Kit ◽  
Healthy Control ◽  
One Step ◽  
Substantial Heterogeneity

To assess the diagnostic performance of lateral flow immunochromatographic assays (LFA) of four different manufacturers to identify SARS-CoV-2 antibodies (IgM, IgG or total), comparing them with the nucleic acid amplification test (NAAT) or clinical defined (definite or probable SARS-CoV-2 infection respectively). Methods. 119 serum samples were randomly selected by convenience and distributed in the groups: (1) Group with SARS-CoV-2 infection [n=82; RT-qPCR positive (definite, n=70), and probable (n=12)]; (2) other diseases [n= 27; other viruses identified (n=8), SARS of other etiologies (n=19)]; (3) healthy control group (n=10). LFA essays of four manufacturers were compared: MedTest Coronavírus (COVID-19) IgG/IgM (MedLevensohn, Brazil); COVID-19 IgG/IgM ECO Test (Ecodiagnóstica, Brazil); Camtech COVID-19 IgM/IgG Rapid Test Kit (Camtech Diagnostics Pte Ltd, Singapore); and one Step COVID-19 Test for total antibodies (Guangzhou Wondfo Biotech Co, China). Results. The four tests studied showed high diagnostic performance characteristics for the diagnoses of definite or probable SARS-CoV-2 infection. The best measures were for the Wondfo test: sensitivity (86.59%; 95%CI, 77.26-93.11%); specificity (100%; 90.51-100%); DOR (257; 60-1008); LR+ (33.43; 4.82-231.85); LR− (0.13; 0.08 - 0.23); accuracy (90.76%; 84.06- 95.29%); Matthews Correlation coefficient (MCC) 0.82. Although considering only the probable SARS-CoV-2 infection (PCR-) cases, all the kits studied showed limited values. Conclusion. Our data demonstrate the excellent performance of LFA for the diagnoses of definite or probable SARS-CoV-2 infection. There was substantial heterogeneity in sensitivities of IgM and IgG antibodies among the manufacturers. LFA tests cannot replace molecular diagnostics, but should be used as additional screening tool.

scholarly journals Seroprevalence, waning, and correlates of anti-SARS-CoV-2 IgG antibodies in Tyrol, Austria: Large-scale study of 35,193 blood donors conducted between June 2020 and September 2021

2021 ◽  
Author(s):  
Anita Siller ◽  
Lisa Seekircher ◽  
Gregor A Wachter ◽  
Manfred Astl ◽  
Lena Tschiderer ◽  
...  
Keyword(s):  
Large Scale ◽  
Blood Donors ◽  
Participation Rate ◽  
Federal State ◽  
Igg Antibodies ◽  
Serum Samples ◽  
Serological Tests ◽  
Nucleocapsid Proteins ◽  
Antibody Levels ◽  
Prior Infection

Background: There is uncertainty about the seroprevalence of anti-SARS-CoV-2 antibodies in the general population of Austria, and about the extent to which antibodies elicited by vaccination or infection wane over time. Aim: To estimate seroprevalence, waning, and correlates of anti-SARS-CoV-2 IgG antibodies in the Federal State of Tyrol, Austria. Methods: We conducted a seroepidemiological study between June 2020 and September 2021, enrolling blood donors aged 18-70 years across Tyrol, Austria (participation rate 84.0%). We analysed serum samples for antibodies against spike or nucleocapsid proteins of SARS-CoV-2 with Abbott SARS-CoV-2 IgG assays. Results: We performed 47,363 serological tests among 35,193 individuals (median age 43.1 years [IQR: 29.3-53.7], 45.3% women, 10.0% with prior SARS-CoV-2 infection). Seroprevalence increased from 3.4% (95% CI: 2.8-4.2%) in June 2020 to 82.7% (95% CI: 81.4-83.8%) in September 2021, largely due to vaccination. Anti-spike IgG seroprevalence was 99.6% (99.4-99.7%) among fully vaccinated individuals, 90.4% (88.8-91.7%) among unvaccinated with prior infection, and 11.5% (10.8-12.3%) among unvaccinated without known prior infection. Anti-spike IgG levels were reduced by 44.0% (34.9-51.7%) at 5-6 months compared to 0-3 months after infection. In fully vaccinated individuals, they decreased by 31.7% (29.4-33.9%) per month. In multivariable adjusted analyses, both seropositivity among unvaccinated and antibody levels among fully vaccinated individuals were higher at young age (<25 years), higher with a known prior infection, and lower in current smokers. Conclusion: Seroprevalence in Tyrol increased to 82.7% in September 2021, with the bulk of seropositivity stemming from vaccination. Antibody levels substantially and gradually declined after vaccination or infection.

scholarly journals Comparison of Coombs Gel Test with ELISA and Standard Tube Agglutination Tests Used in Serological Diagnosis of Brucellosis

2020 ◽  
Vol 2 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Cigdem Akalan Kuyumcu ◽  
Serpil Erol ◽  
Rıza Adaleti ◽  
Seniha Senbayrak ◽  
Secil Deniz ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Diagnostic Tests ◽  
Serological Test ◽  
High Sensitivity ◽  
Serological Diagnosis ◽  
Control Groups ◽  
Serum Samples ◽  
Serological Tests ◽  
Reliable Test ◽  
And Control

Objective: Serological tests are the most commonly used tests in the diagnosis of brucellosis; however, each serological test has some drawbacks. In this study, we aimed to determine the value of the Brucella Coombs gel test (BCGT) in the serological diagnosis of brucellosis in comparison with Standard tube agglutination (STA) and ELISA tests. Materials and Methods: The study included 42 patients who were considered to have brucellosis as a preliminary diagnosis. BCGT, Brucella-IgM/IgG ELISA, and STA tests were performed from serum samples of the patients. The correlation of the diagnostic tests was analyzed using Cohen’s Kappa Analysis.  Results: Twenty-seven (64.2%) of 42 patients were diagnosed with brucellosis according to their medical history and clinical and serological tests. The sensitivity and specificity of BCGT to diagnose brucellosis was 96.2%, and 100%, respectively. The sensitivity and specificity for the diagnosis of brucellosis 62.9% and 100% for STA, respectively; 33.3% and 66.6% for Brucella-IgM; and 66.6% and 100% for Brucella-IgG. BCGT was significantly correlated with STA (κ= 0.590) and Brucella-IgG (κ=0.539) Conclusion: BCGT can be utilized as a simple and reliable test in the diagnosis of brucellosis with high sensitivity and specificity. Nevertheless, the sensitivity and specificity of BCGT should be demonstrated by comprehensive studies, including culture-confirmed cases and control groups.

Clinical and diagnostic manifestations of tickborne mixed infection in combination with COVID-19

2021 ◽  
Vol 66 (11) ◽  
pp. 689-694
Author(s):  
A. L. Shutikova ◽  
G. N. Leonova ◽  
A. F. Popov ◽  
M. Yu. Shchelkanov
Keyword(s):  
Lyme Disease ◽  
Erythema Migrans ◽  
Clinical Manifestations ◽  
Underlying Disease ◽  
Laboratory Diagnostics ◽  
Igg Antibodies ◽  
Serum Samples ◽  
Igm Antibodies ◽  
Chronic Encephalitis ◽  
Tbev Strain

The coexistence of various pathogens inside the patient’s body is one of the poorly studied and current issues. The aim of the study is to identify the relationship between the indicators of complex laboratory diagnostics and the clinical manifestations of a mixed disease during subsequent infection with the SARS-CoV-2 virus using the example of a case of chronic encephalitis-borreliosis infection. Seven blood serum samples were collected from the patient over the course of a year. For the etiological verification of the causative agents of TBE, Lyme disease and COVID-19, the methods of ELISA and PCR diagnostics were used. The patient was diagnosed with Lyme disease on the basis of the detection of IgG antibodies to Borrelia 5 months after the onset of the disease, since she denied the tick bite. In the clinical picture, there was an articular syndrome and erythema migrans. Later, IgG antibodies to the TBEV were found in the blood. Throughout the study, IgM antibodies to Borrelia were not detected. The exacerbation of Lyme disease could be judged by the clinical manifestations of this disease and by the growth of specific IgG antibodies. A feature of this case was that during an exacerbation of the Lyme disease, an infection with the SARS-CoV-2 virus occurred. Treatment (umifenovir, hydroxychloroquine, azithromycin, ceftriaxone) was prescribed, which improved the condition of the underlying disease, decreased joint pain, decreased IgG levels to borrelia. However, during this period, serological markers of TBEV appear: antigen, IgM antibodies, and the titer of IgG antibodies increases. Most likely, this was facilitated by the switching of the immune system to the SARS-CoV-2 virus, with the simultaneous suppression of borrelia with antibiotics and the appointment of hydroxychloroquine, which has an immunosuppressive effect. Despite the activation of the virus, clinical manifestations of TBE were not observed in the patient, which is most likely associated with infection with a weakly virulent TBEV strain. The further course of tick-borne infections revealed the dominant influence of B. burgdorferi in relation to TBEV. Laboratory studies have shown that suppression of the activity of the borreliosis process by etiotropic treatment subsequently led to the activation of the persistent TBEV.

Evaluation of reactivity to Echinococcus spp. among rural inhabitants in Poland

2015 ◽  
Vol 60 (3) ◽  
Author(s):  
Ewa Cisak ◽  
Jacek Sroka ◽  
Angelina Wójcik-Fatla ◽  
Violetta Zając ◽  
Jacek Dutkiewicz
Keyword(s):  
Western Blot ◽  
Echinococcus Granulosus ◽  
Cross Reactivity ◽  
Farm Animals ◽  
Control Group ◽  
Laboratory Diagnostics ◽  
Group 14 ◽  
Serum Samples ◽  
The City ◽  
Echinococcus Spp

AbstractA group of 172 rural inhabitants from eastern Poland (68 males and 104 females, mean age 49.0 ± 12.0 years) was examined for the presence of antibodies against Echinococcus granulosus and Echinococcus multilocularis. A population of 38 healthy urban dwellers from the city of Lublin (17 males and 21 females, mean age 36.2 ± 9.6 years) were examined as a control group. Sera of 22 rural inhabitants (12.8%) reacted positively to Echinococcus granulosus hydatid fluid antigen in the screening test. A cross-reactivity was observed with two serum samples that tested positive in ELISA for E. granulosus. Three serum samples were tested positive for E. multilocularis using the Em2plus ELISA assay and also positive for Western blot. None of the members of control group showed the presence of a seropositive reaction to Echinococcus spp. The reactivity to Echinococcus spp. among rural inhabitants decreased with age and this correlation was statistically significant (R = -0.197151, p = 0.009535). The percentage of positive findings was the highest (50.0%) in the youngest age group (14-20). No significant correlations were found between responses to interview questions (possession of domestic and farm animals, contact with wild animals, eating unwashed berries, drinking unboiled water) and the presence of seropositive reactions to Echinococcus spp. The presented results seem to indicate that echinococcosis is still a current problem in Poland that should not be neglected and, moreover, indicates the need for improvement in the routine laboratory diagnostics of Echinococcus spp. by standardizing the ELISA and Western blot tests.

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