scholarly journals Evaluation of Eleven SARS-CoV-2 Antibody Tests by using Samples from Patients with Defined IgG Antibody Titers

2021 ◽  
Author(s):  
Nina Lagerqvist ◽  
Kimia Maleki ◽  
Jenny Verner-Carlsson ◽  
Mikaela Olausson ◽  
Joakim Dillner ◽  
...  
Keyword(s):  
Symptom Onset ◽  
Diagnostic Tests ◽  
Immunofluorescence Assay ◽  
Rapid Diagnostic Tests ◽  
The Other ◽  
Igg Antibody ◽  
Reference Set ◽  
Antibody Titers ◽  
Serial Samples ◽  
Antibody Tests

Abstract We evaluated the performance of eleven SARS-CoV-2 antibody tests using a reference set of heat-inactivated samples from 278 unexposed persons and 258 COVID-19 patients, some of whom contributed serial samples. The reference set included samples with a variation in SARS-CoV-2 IgG antibody titers, as determined by an in-house immunofluorescence assay (IFA). The five evaluated rapid diagnostic tests had an IgG-based specificity of 99.0% and a sensitivity that ranged from 56.3–81.6% and decreased with low IFA titers. The specificity was > 99% for five out of six platform-based tests, and when assessed using samples collected ≥ 22 days after symptom onset, two assays had a sensitivity of > 96%. These two assays also detected samples with low IFA titers more frequently than the other assays. In conclusion, the evaluated antibody tests showed a heterogeneity in their performances and only a few tests performed well with samples having low IFA IgG titers, an important aspect for diagnostics and epidemiological investigations.

scholarly journals Evaluation of 11 SARS-CoV-2 antibody tests by using samples from patients with defined IgG antibody titers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nina Lagerqvist ◽  
Kimia T. Maleki ◽  
Jenny Verner-Carlsson ◽  
Mikaela Olausson ◽  
Joakim Dillner ◽  
...  
Keyword(s):  
Symptom Onset ◽  
Diagnostic Tests ◽  
Immunofluorescence Assay ◽  
Rapid Diagnostic Tests ◽  
The Other ◽  
Igg Antibody ◽  
Reference Set ◽  
Antibody Titers ◽  
Serial Samples ◽  
Antibody Tests

AbstractWe evaluated the performance of 11 SARS-CoV-2 antibody tests using a reference set of heat-inactivated samples from 278 unexposed persons and 258 COVID-19 patients, some of whom contributed serial samples. The reference set included samples with a variation in SARS-CoV-2 IgG antibody titers, as determined by an in-house immunofluorescence assay (IFA). The five evaluated rapid diagnostic tests had a specificity of 99.0% and a sensitivity that ranged from 56.3 to 81.6% and decreased with low IFA IgG titers. The specificity was > 99% for five out of six platform-based tests, and when assessed using samples collected ≥ 22 days after symptom onset, two assays had a sensitivity of > 96%. These two assays also detected samples with low IFA titers more frequently than the other assays. In conclusion, the evaluated antibody tests showed a heterogeneity in their performances and only a few tests performed well with samples having low IFA IgG titers, an important aspect for diagnostics and epidemiological investigations.

scholarly journals Evaluation of two new rapid diagnostic tests (RDTs) for the diagnosis of malaria

2013 ◽  
Vol 5 (2) ◽  
pp. 11-15 ◽  
Author(s):  
Fahmida Jahan ◽  
Rubayet Elahi ◽  
Md. Khaja Mohiuddin ◽  
Md. Gulam Musawwir Khan ◽  
Mohammad Shafiul Alam ◽  
...  
Keyword(s):  
Predictive Value ◽  
Gold Standard ◽  
Diagnostic Tests ◽  
Rapid Diagnostic Tests ◽  
Accurate Diagnosis ◽  
The Other ◽  
Antibody Detection ◽  
Resource Limited Settings ◽  
Malaria Rdts ◽  
Resource Limited

Rapid diagnostic tests (RDTs) address the need for accurate diagnosis of malaria, particularly in resource limited settings. In this study, two malaria RDTs were compared with gold standard microscopy: On Site Pf/Pv test detecting Plasmodium falciparum-specific histidine rich protein-2 (Pf HR P2) and P. vivax-specific parasitic lactate dehydrogenase (pLDH) antigens; and SD Bioline anti-Pf/Pv test detecting anti-HR P2 and anti-pL DH antibodies for the diagnosis of P. falciparum and P. vivax infections, respectively. For OnSite test, the overall sensitivity was found 96.2% , specificity 98.2% , positive predictive value (PPV ) 98.2% , negative predictive value (NPV ) 96.4% and agreement with microscopy was found to be 0.94. On the other hand SD Bioline test, the overall sensitivity was 75.4%, specificity 83.7%, PPV 84.3% , NPV 74.5% and agreement with microscopy was 0.59. These data revealed that the R DT based on antigen detection (Onsite test) was more reliable than that based on the antibody detection (SD Bioline test).DOI: http://dx.doi.org/10.3329/bjmm.v5i2.16931 Bangladesh J Med Microbiol 2011; 05 (02): 11-15

scholarly journals Frequency of antibodies and risk factors associated with Toxoplasma gondii infection in backyard pig production in the city of Mossoró, state of Rio Grande do Norte, Brazil

2019 ◽  
Vol 28 (3) ◽  
pp. 508-513 ◽  
Author(s):  
Isabela Maria Campanelli dos Santos ◽  
Alexandro Iris Leite ◽  
Maria Eduarda Chiaradia Furquim ◽  
Diego Carlos de Souza Zanatto ◽  
Simone de Jesus Fernandes ◽  
...  
Keyword(s):  
Risk Factors ◽  
Rio Grande ◽  
Female Gender ◽  
Immunofluorescence Assay ◽  
P Value ◽  
Serum Samples ◽  
Igg Antibody ◽  
Source Of Infection ◽  
Antibody Titers ◽  
Toxoplasma Gondii Infection

Abstract Toxoplasmosis is an important zoonosis for pregnant women and immunosuppressed people. The pig population also becomes infected by this pathogen, and undercooked or raw meat is an important source of infection for humans. The aims of the present study were to evaluate the rate of exposure of pigs to T. gondii in the municipality of Mossoró, Rio Grande do Norte and seek to identify associations with possible risk factors. Blood samples were collected from 412 pigs and were analyzed using the immunofluorescence assay. Among these 412 serum samples, 40.7% were seropositive for T. gondii. The IgG antibody titers were 64 (56 specimens), 128 (32), 256 (37), 512 (23), 1024 (14), 2048 (5) and 4046 (1). Seropositivity for T. gondii was found to be related (p-value < 0.05) to the following factors: female gender, semi-confined rearing system, use of well water, dewormed animals, presence of cats, goats, sheep, mice and vultures on the farm and carcasses left on the ground. In contrast, seropositivity was not related (p-value < 0.05) to the age of the pigs, type of facility or feeding with human food remains. Preventive measures need to be adopted on the farms studied here, with the aim of decreasing the animals’ intake of sporulated oocysts.

scholarly journals DIAGNOSIS OF MALARIA INFECTION WITH OR WITHOUT DISEASE

2012 ◽  
Vol 4 (1) ◽  
pp. e2012036 ◽  
Author(s):  
Zeno Bisoffi ◽  
Federico Gobbi ◽  
Dora Buonfrate ◽  
Jef Van den Ende
Keyword(s):  
Diagnostic Tests ◽  
Malaria Infection ◽  
Cost Effective ◽  
Clinical Malaria ◽  
Rapid Diagnostic Tests ◽  
The Other ◽  
Adults And Children ◽  
Fever Management ◽  
Positive Results ◽  
Very High

The revised W.H.O. guidelines for malaria management in endemic countries recommend that treatment should be reserved to laboratory confirmed cases, both for adults and children. Currently the most widely used tools are rapid diagnostic tests (RDTs), that are accurate and reliable in diagnosing malaria infection. However, an infection is not necessarily a clinical malaria, and RDTs may give positive results in febrile patients who have another cause of fever. Excessive reliance on RDTs may cause overlooking potentially severe non malarial febrile illnesses (NMFI) in these cases. In countries or areas where transmission intensity remains very high, fever management in children (especially in the rainy season) should probably remain presumptive, as a test-based management may not be safe, nor cost effective. In contrast, in countries with low transmission, including those targeted for malaria elimination, RDTs are a key resource to limit unnecessary antimalarial prescription and to identify pockets of infected individuals. Research should focus on very sensitive tools for infection on one side, and on improved tools for clinical management on the other, including biomarkers of clinical malaria and/or of alternative causes of fever.

scholarly journals Performance Evaluation of the Siemens SARS-CoV-2 Total Antibody and IgG Antibody Test

2021 ◽  
Author(s):  
Lisa Florin ◽  
Karel Maelegheer ◽  
Wouter Vandewal ◽  
Dirk Bernard ◽  
Johan Robbrecht
Keyword(s):  
Antibody Test ◽  
Control Group ◽  
Igg Antibody ◽  
Antibody Assays ◽  
Antibody Titers ◽  
Polymerase Chain ◽  
Kinetics Of ◽  
Antibody Tests ◽  
Positive Controls

Abstract Objective In this study, the performance of 2 commercially available SARS-CoV-2 antibody assays is evaluated. Methods The Siemens SARS-CoV-2 Total (COV2T) and IgG (COV2G) antibody tests were evaluated on a Siemens Atellica IM1300 analyzer. Imprecision was assessed with the CLSI EP15 protocol using positive controls. Ninety control group specimens were analyzed for specificity, and 175 specimens from 58 patients with polymerase chain reaction–confirmed SARS-CoV-2 were measured for the sensitivity and kinetics of the antibody response. Results Within-run and total imprecision were acceptable for both assays. Both tests showed a specificity of 100%. Sensitivity earlier in the disease state was greater for the COV2T assay than for the COV2G assay, but sensitivity &gt;14 days after onset of symptoms approached 100% for both. For all patients, antibody titers remained above the seroconversion cutoff for all follow-up specimens. Conclusion This study shows acceptable performance for both the Siemens COV2T and COV2G test, although seroconversion occurs earlier with the COV2T test.

scholarly journals Seroprevalence of Toxoplasma gondii infection in cats from Curitiba, Paraná, Brazil

2011 ◽  
Vol 20 (3) ◽  
pp. 256-258 ◽  
Author(s):  
Marúcia de Andrade Cruz ◽  
Leila Sabrina Ullmann ◽  
Patrícia Yukiko Montaño ◽  
Juliano Leônidas Hoffmann ◽  
Helio Langoni ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Dietary Habits ◽  
Immunofluorescence Assay ◽  
Serum Samples ◽  
Igg Antibody ◽  
Veterinary Clinic ◽  
Warm Blood ◽  
Potential Risk Factors ◽  
Antibody Titers ◽  
Toxoplasma Gondii Infection

Toxoplasmosis is a worldwide zoonosis caused by the protozoa Toxoplasma gondii which infects all warm-blood vertebrates. This study aimed to assess the seroprevalence of anti-Toxoplasma gondii antibodies in a population of domestic cats seen at a major cat-only veterinary clinic in Curitiba, Paraná State, Southern Brazil. Serum samples were processed by indirect immunofluorescence assay (IIFA) for the detection of IgG. Antibody titers were found in 16.3% (46/282) of sera analyzed, with titers to T. gondii of 16 in eight cats, 64 in 23 cats, 256 in 14 cats and 1024 in one cat. Statistical differences were not found regarding the association with age, gender and different areas of the city (p > 0.05). No significant differences were found in any variable when comparing seropositivity with potential risk factors. The seroprevalence was relatively lower when compared to other Brazilian regions, probably due to the fact that the cats studied were owned, domiciled with restricted dietary habits based on processed foods, restricted access to the street and no prey access. In conclusion, low feline toxoplasmosis seroprevalence may be associated to owned cats due to adequate dietary care and restricted outdoor access, as well as low local environmental exposure.

Infection by Coxiella burnetii in a patient from a rural area of Monteria, Colombia

2015 ◽  
Vol 16 (6) ◽  
pp. 958-961 ◽  
Author(s):  
Salim Mattar V ◽  
Verónica Contreras C ◽  
Marco Gonzalez T ◽  
Francisco Camargo ◽  
Jaime Alvarez ◽  
...  
Keyword(s):  
Phase I ◽  
Rural Area ◽  
Phase Ii ◽  
Coxiella Burnetii ◽  
Indirect Immunofluorescence ◽  
Q Fever ◽  
Immunofluorescence Assay ◽  
Indirect Immunofluorescence Assay ◽  
Igg Antibody ◽  
Antibody Titers

<p>Q fever is a zoonosis caused by <em>Coxiella burnetii</em>. In Colombia, there have been very few human cases reported to date. This report describes the case of a 56-year-old patient with a background in agriculture and livestock handling. An indirect immunofluorescence assay (IFA) showed high titers of IgG for <em>C. burnetii</em> anti-phase I (1: 256) and anti-phase II (1:1024). For the next six months the patient’s IgG antibody titers remained high, and, after treatment with doxycycline, the IgG antibody titers decreased to 50 % (anti-phase I 1:128 and anti-phase II 1:512); this profile suggests an infection of <em>C. burnetii</em>.</p>

scholarly journals COVID-19 symptoms, duration, and prevalence among healthcare workers in the New York metropolitan area

2020 ◽  
pp. 1-7
Author(s):  
Fran A. Ganz-Lord ◽  
Kathryn R. Segal ◽  
Michael L. Rinke
Keyword(s):  
New York ◽  
Return To Work ◽  
Sore Throat ◽  
Symptom Onset ◽  
Healthcare Workers ◽  
Shortness Of Breath ◽  
Antibody Testing ◽  
Igg Antibody ◽  
York Metropolitan Area ◽  
Antibody Tests

Abstract Objective: To evaluate symptoms, workforce implications, and testing patterns related to the coronavirus disease 2019 (COVID-19) pandemic among healthcare workers (HCWs) in the New York metropolitan area during spring 2020. Design: Retrospective cohort study of occupational health services (OHS) records. Setting: A large, urban, academic medical center with 5 inpatient campuses and multiple ambulatory centers throughout Bronx and Westchester counties. Participants: We included HCWs who called OHS to report COVID-19 symptoms and had either severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction (PCR) or IgG antibody testing. Methods: We analyzed the impact of COVID-19–related symptoms on (1) time from symptom onset to return to work, (2) the results of SARS-CoV-2 nasopharyngeal PCR testing, and (3) the results of SARS-CoV-2 IgG antibody testing in HCWs with mild-to-moderate COVID-19. Results: The median time from symptom onset until return to work for HCWs who did not require hospitalization was 15 days (interquartile range, 10–22). Shortness of breath, fever, sore throat, and diarrhea were significantly associated with longer durations from symptom onset to return to work. Among symptomatic HCWs who had PCR testing during the study period, 51.9% tested positive. Of the previously symptomatic HCWs who had IgG antibody testing, 55.4% had reactive tests. Ageusia was associated with having both positive PCR and reactive antibody tests. Sore throat was associated with both negative PCR and nonreactive antibody tests. Conclusion: HCWs with COVID-19 who did not require hospitalization still had prolonged illness. Shortness of breath, fever, sore throat, and diarrhea are associated with longer durations of time away from work.

Sign in / Sign up

Export Citation Format

Share Document