Evaluation of Three Point-of-Care Tests for Detection of Toxoplasma Immunoglobulin IgG and IgM in the United States: Proof of Concept and Challenges

Abstract Background The cost of conventional serological testing for toxoplasmosis discourages universal adoption of prenatal monthly screening programs to prevent congenital toxoplasmosis. Point-of-care (POC) technology may constitute a cost-effective approach. Methods We evaluated the diagnostic accuracy of 3 Toxoplasma POC tests against gold-standard testing performed at Palo Alto Medical Foundation Toxoplasma Serology Laboratory (PAMF-TSL). The POC tests included the following: Toxo IgG/IgM Rapid Test (Biopanda) and the OnSite Toxo IgG/IgM Combo-Rapid-test that detect IgG and IgM separately, and the Toxoplasma ICT-IgG-IgM-bk (LDBIO) that detects either or both immunoglobulin IgG/IgM in combination. Samples were selected from PAMF-TSL biobank (n = 210) and Centers for Disease Control and Prevention Toxoplasma 1998 Human Serum Panel (n = 100). Based on PAMF-TSL testing, Toxoplasma-infection status was classified in 4 categories: acute infections (n = 85), chronic infections (n = 85), false-positive Toxoplasma IgM (n = 60), and seronegative (n = 80). The POC testing was performed in duplicate following manufacturer’s instructions by investigators blinded to PAMF-TSL results. Sensitivity and specificity were calculated. Results A total of 1860 POC tests were performed. For detection of Toxoplasma IgG, sensitivity was 100% (170 of 170; 95% confidence interval [CI], 97.8%–100%) for all 3 POC kits; specificity was also comparable at 96.3% (77 of 80; 95% CI, 89.5%–98.9%), 97.5% (78 of 80; 95% CI, 91.3%–99.6%), and 98.8% (79 of 80; 95% CI, 93.2%–99.9%). However, sensitivity for detection of Toxoplasma IgM varied significantly across POC tests: Biopanda, 62.2% (51 of 82; 95% CI, 51.4%–71.9%); OnSite, 28% (23 of 82; 95% CI, 19.5%–38.6%); and LDBIO combined IgG/IgM, 100% (82 of 82; 95% CI, 95.5%–100%). Diagnostic accuracy was significantly higher for the LDBIO POC kit. The POC kits did not exhibit cross-reactivity for false-positive Toxoplasma-IgM sera. Conclusions The 3 evaluated POC kits revealed optimal sensitivity for Toxoplasma-IgG antibodies. The LDBIO-POC test exhibited 100% sensitivity for the combined detection of IgG/IgM in acute and chronic Toxoplasma infection. Biopanda and Onsite POC tests exhibited poor sensitivity for Toxoplasma-IgM detection.

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Updated Clinical Evaluation of the CLUNGENE® Rapid COVID-19 Antibody Test

Healthcare ◽

10.3390/healthcare9091124 ◽

2021 ◽

Vol 9 (9) ◽

pp. 1124

Author(s):

Christopher C. Lamb ◽

Fadi Haddad ◽

Christopher Owens ◽

Alfredo Lopez-Yunez ◽

Marion Carroll ◽

...

Keyword(s):

False Positive ◽

Point Of Care ◽

Rapid Test ◽

Antibody Test ◽

Cross Reactivity ◽

Blood Collection ◽

Rt Pcr ◽

Antibody Testing ◽

Reactivity Study ◽

Positive Results

Background: COVID-19 antibody testing has been shown to be predictive of prior COVID-19 infection and an effective testing tool. The CLUNGENE® SARS-COV-2 VIRUS (COVID-19) IgG/IgM Rapid Test Cassette was evaluated for its utility to aide healthcare professionals. Method: Two studies were performed by using the CLUNGENE® Rapid Test. (1) An expanded Point-of-Care (POC) study at two clinical sites was conducted to evaluate 99 clinical subjects: 62 positive subjects and 37 negative subjects were compared to RT-PCR, PPA, and NPA (95% CI). Sensitivity was calculated from blood-collection time following symptom onset. (2) A cross-reactivity study was performed to determine the potential for false-positive results from other common infections. Results: The specificity of subjects with confirmed negative COVID-19 by RT-PCR was 100% (95% CI, 88.4–100.0%). The sensitivity of subjects with confirmed positive COVID-19 by RT-PCR was 96.77% (95% CI, 88.98–99.11%). In the cross-reactivity study, there were no false-positive results due to past infections or vaccinations unrelated to the SARS-CoV-2 virus. Conclusion: There is a need for a rapid, user-friendly, and inexpensive on-site monitoring system for diagnosis. The CLUNGENE® Rapid Test is a useful diagnostic test that provides results within 15 min, without high-complexity laboratory instrumentation.

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Potential Antigenic Cross-reactivity Between Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and Dengue Viruses

Clinical Infectious Diseases ◽

10.1093/cid/ciaa1207 ◽

2020 ◽

Cited By ~ 9

Author(s):

Yaniv Lustig ◽

Shlomit Keler ◽

Rachel Kolodny ◽

Nir Ben-Tal ◽

Danit Atias-Varon ◽

...

Keyword(s):

Severe Acute Respiratory Syndrome ◽

Envelope Protein ◽

False Positive ◽

In Silico ◽

Rapid Test ◽

Cross Reactivity ◽

Lateral Flow ◽

Immunoglobulin M ◽

Enzyme Linked Immunosorbent Assay ◽

Elisa Testing

Abstract Background Coronavirus disease 2019 (COVID-19) and dengue fever are difficult to distinguish given shared clinical and laboratory features. Failing to consider COVID-19 due to false-positive dengue serology can have serious implications. We aimed to assess this possible cross-reactivity. Methods We analyzed clinical data and serum samples from 55 individuals with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. To assess dengue serology status, we used dengue-specific antibodies by means of lateral-flow rapid test, as well as enzyme-linked immunosorbent assay (ELISA). Additionally, we tested SARS-CoV-2 serology status in patients with dengue and performed in-silico protein structural analysis to identify epitope similarities. Results Using the dengue lateral-flow rapid test we detected 12 positive cases out of the 55 (21.8%) COVID-19 patients versus zero positive cases in a control group of 70 healthy individuals (P = 2.5E−5). This includes 9 cases of positive immunoglobulin M (IgM), 2 cases of positive immunoglobulin G (IgG), and 1 case of positive IgM as well as IgG antibodies. ELISA testing for dengue was positive in 2 additional subjects using envelope protein directed antibodies. Out of 95 samples obtained from patients diagnosed with dengue before September 2019, SARS-CoV-2 serology targeting the S protein was positive/equivocal in 21 (22%) (16 IgA, 5 IgG) versus 4 positives/equivocal in 102 controls (4%) (P = 1.6E−4). Subsequent in-silico analysis revealed possible similarities between SARS-CoV-2 epitopes in the HR2 domain of the spike protein and the dengue envelope protein. Conclusions Our findings support possible cross-reactivity between dengue virus and SARS-CoV-2, which can lead to false-positive dengue serology among COVID-19 patients and vice versa. This can have serious consequences for both patient care and public health.

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Evaluation of the diagnostic accuracy of a new point-of-care rapid test for SARS-CoV-2 virus detection

10.21203/rs.3.rs-100047/v1 ◽

2020 ◽

Author(s):

Leonardo Miscio ◽

Antonio Olivieri ◽

Francesco Labonia ◽

Gianfranco De Feo ◽

Paolo Chiodini ◽

...

Keyword(s):

Diagnostic Accuracy ◽

Real Time ◽

Real Time Pcr ◽

Point Of Care ◽

Virus Detection ◽

Rapid Test ◽

Reference Method ◽

Standard Of Care ◽

Easy Access ◽

Diagnostic Tools

Abstract Background: The easy access to a quick diagnosis of coronavirus disease 2019 (COVID-19) is a key point to improve the management of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and to contain its spread. Up to now, laboratory real-time PCR is the standard of care, but requires a fully equipped laboratory and significant infrastructure. Consequently, new diagnostic tools are required. Methods: In the present work, the diagnostic accuracy of the point-of-care rapid test "bKIT Virus Finder COVID-19" (Hyris Ltd) is evaluated by a retrospective and a prospective analysis on SARS CoV-2 samples previously assessed with an FDA “authorized for the emergency use - EUA” reference method. Descriptive statistics were used for the present study.Results: Results obtained with the Hyris Kit are the same as that of standard laboratory-based real time PCR methods for all the analyzed samples. In addition, the Hyris Kit provides the test results in less than 2 hours, a significantly shorter time compared to the reference methods, without the need of a fully equipped laboratory. Conclusions: To conclude, the Hyris kit represents a promising tool to improve the health surveillance and to increase the capacity of SARS-CoV-2 testing.

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Diagnostic accuracy of two commercial SARS-CoV-2 antigen-detecting rapid tests at the point of care in community-based testing centers

PLoS ONE ◽

10.1371/journal.pone.0248921 ◽

2021 ◽

Vol 16 (3) ◽

pp. e0248921

Author(s):

Alice Berger ◽

Marie Therese Ngo Nsoga ◽

Francisco Javier Perez-Rodriguez ◽

Yasmine Abi Aad ◽

Pascale Sattonnet-Roche ◽

...

Keyword(s):

Diagnostic Accuracy ◽

Point Of Care ◽

Rapid Test ◽

Diagnostic Value ◽

Ease Of Use ◽

Lower Sensitivity ◽

Rt Pcr ◽

Test Device ◽

Community Based ◽

Rapid Tests

Objectives Determine the diagnostic accuracy of two antigen-detecting rapid diagnostic tests (Ag-RDT) for SARS-CoV-2 at the point of care and define individuals’ characteristics providing best performance. Methods We performed a prospective, single-center, point of care validation of two Ag-RDT in comparison to RT-PCR on nasopharyngeal swabs. Results Between October 9th and 23rd, 2020, 1064 participants were enrolled. The PanbioTM Covid-19 Ag Rapid Test device (Abbott) was validated in 535 participants, with 106 positive Ag-RDT results out of 124 positive RT-PCR individuals, yielding a sensitivity of 85.5% (95% CI: 78.0–91.2). Specificity was 100.0% (95% CI: 99.1–100) in 411 RT-PCR negative individuals. The Standard Q Ag-RDT (SD Biosensor, Roche) was validated in 529 participants, with 170 positive Ag-RDT results out of 191 positive RT-PCR individuals, yielding a sensitivity of 89.0% (95%CI: 83.7–93.1). One false positive result was obtained in 338 RT-PCR negative individuals, yielding a specificity of 99.7% (95%CI: 98.4–100). For individuals presenting with fever 1–5 days post symptom onset, combined Ag-RDT sensitivity was above 95%. Lower sensitivity of 88.2% was seen on the same day of symptom development (day 0). Conclusions We provide an independent validation of two widely available commercial Ag-RDTs, both meeting WHO criteria of ≥80% sensitivity and ≥97% specificity. Although less sensitive than RT-PCR, these assays could be beneficial due to their rapid results, ease of use, and independence from existing laboratory structures. Testing criteria focusing on patients with typical symptoms in their early symptomatic period onset could further increase diagnostic value.

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False-Positive Tuberculin Skin Test Results Among Low-Risk Healthcare Workers Following Implementation of Fifty-Dose Vials of Purified Protein Derivative

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2018.59 ◽

2018 ◽

Vol 39 (6) ◽

pp. 750-752 ◽

Cited By ~ 1

Author(s):

Jeffrey M. Collins ◽

Mary Hunter ◽

Wanda Gordon ◽

Russell R. Kempker ◽

Henry M. Blumberg ◽

...

Keyword(s):

Tuberculin Skin Test ◽

Skin Test ◽

False Positive ◽

Healthcare Workers ◽

Large Scale ◽

The United States ◽

Positive Tuberculin Skin Test ◽

Low Risk ◽

Test Results ◽

Screening Programs

Following large declines in tuberculosis transmission the United States, large-scale screening programs targeting low-risk healthcare workers are increasingly a source of false-positive results. We report a large cluster of presumed false-positive tuberculin skin test results in healthcare workers following a change to 50-dose vials of Tubersol tuberculin.Infect Control Hosp Epidemiol 2018;39:750–752

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Current Point-of-Care testing in cancer and future perspectives: a systematic review

European Journal of Public Health ◽

10.1093/eurpub/ckaa040.033 ◽

2020 ◽

Vol 30 (Supplement_2) ◽

Cited By ~ 1

Author(s):

M Rodrigues ◽

I Andrade ◽

R Cruz

Keyword(s):

Systematic Review ◽

Early Detection ◽

Point Of Care ◽

Low Cost ◽

Rapid Test ◽

Point Of Care Testing ◽

Screening Programs ◽

Low Resource ◽

Resource Limited ◽

Prevalent Disease

Abstract Introduction Cancer is the most prevalent disease worldwide, causing a major impact on society. Early detection and monitorization of the tumour can provide a more effective treatment. Point-of-care (POC) testing allows the patient to have a handheld test that gives the results rapidly. No expertise or special knowledge is required which is vital namely when carried out in low-resource areas. Recent studies analysed established and emerging biomarkers and how to incorporate them into POC devices, but a systematic review reporting the existing POC platforms for cancer is still not available. Objectives This systematic review aims to report current and recent advances for point-of-care testing in cancer. Methodology A literature review was conducted through research in the databases “PubMed” and “B-On” for relevant reviews published in the last ten years, using the keywords “Point-of-care testing” AND “Cancer” AND “Rapid Test” AND “Cancer detection”. Results In 2015 there were eight commercially available POC tests for prostate, bladder, colorectal, cervical, HPV-causing head and neck cancer, liver, breast and lung cancer. After 2018 a small number of POC devices were tested in screening programs and multicentric studies, and more recently, promising novel POC prototypes for early detection of cancer, namely a 3D prototype micro device for multiple singleplex RNA expression analysis in liver cancer and a POC microscopy prototype for digital diagnostics of breast cancer lymph node metastases, with potential to be used in resource-limited settings. Conclusion The use of POC testing can deliver accurate, fast results, and in the case of cancer it is no exception, contributing to the progression of treatment and reduction in cancer-related deaths. In low-resource settings a POC test is fundamental and it should be simple and low-cost. But there are limitations in the tests which is a challenge for improvement and investigation in the future.

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Use of Oral Fluid in a Rapid Syphilis Test Assay

Open Forum Infectious Diseases ◽

10.1093/ofid/ofx163.107 ◽

2017 ◽

Vol 4 (suppl_1) ◽

pp. S107-S108 ◽

Cited By ~ 1

Author(s):

Chelsea Shannon ◽

Claire Bristow ◽

Sasha Herbst De Cortina ◽

Jennifer Chang ◽

Jeffrey Klausner

Keyword(s):

Whole Blood ◽

Oral Fluid ◽

Point Of Care ◽

Fluid Collection ◽

Treponema Pallidum ◽

Rapid Test ◽

High Sensitivity ◽

The United States ◽

Collection Device ◽

Positive Results

Abstract Background From 2014 to 2015, the syphilis rate in the United States increased by 19%, reaching its highest rate since 1994. Currently, point-of-care syphilis assays use fingerstick or venipuncture whole blood to identify Treponema pallidum (TP) antibodies by qualitative immunoassay. However, patients and providers prefer oral fluid testing to whole blood testing. In this study, we aimed to determine whether a rapid syphilis test intended for use on whole blood could be used to detect TP antibodies in oral fluid. Methods Oral fluid was collected from 72 participants using the Super•SAL™ Oral Fluid Collection Device (Oasis Diagnostics®, Vancouver, WA). The device uses an absorbent cylindrical pad to collect and filter ~1 mlml of oral fluid. Oral fluid filtrate was tested using the SD Bioline Syphilis 3.0 rapid test (Alere Diagnostics, MA) following manufacturer directions for whole blood. TP particle agglutination (TPPA) and rapid plasma reagin (RPR) results derived from participants’ medical records were used as reference values. We used three different definitions as comparators: 1: TPPA reactive; 2: TPPA and RPR reactive and 3: TPPA reactive and RPR titer >1:4. Those with non-reactive TPPA and RPR results were considered seronegative. We calculated the sensitivity and specificity for definition 1 and sensitivity for definitions 2 and 3. We used the exact binomial method to determine 95% confidence intervals (CI). Results With definitions 1, 2, and 3, respectively, sensitivity was 83.3% (CI: 67.2, 93.6), 86.4% (CI: 65.1, 97.1), and 100% (CI: 71.5, 100). Specificity was 47.2% (CI: 36.5, 75.5). Conclusion The high sensitivity of the SD Bioline Syphilis 3.0 test using oral fluid suggests a strong potential for the development of accurate rapid oral syphilis tests. Sensitivity increased with higher RPR titer. False positive results may be due to the presence of non-venereal treponemal antibodies in oral fluid. Further research and development are needed to optimize specificity. Disclosures All authors: No reported disclosures.

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Diagnostic accuracy of two commercially available rapid assays for detection of IgG and IgM antibodies to SARS-CoV-2 compared to ELISA in a low-prevalence population

10.21203/rs.3.rs-50887/v1 ◽

2020 ◽

Author(s):

Klaus Hackner ◽

Peter Errhalt ◽

Martin Willheim ◽

Maria-Anna Grasl ◽

Jasmina Lagumdzija ◽

...

Keyword(s):

Diagnostic Accuracy ◽

Close Contact ◽

Point Of Care ◽

Rapid Test ◽

Screen Test ◽

Elisa Test ◽

Antibody Detection ◽

Enzyme Linked Immunosorbent Assay ◽

Rapid Assays ◽

Low Prevalence

Abstract Background: New commercially available point-of-care (POC) immunodiagnostic tests are appearing, which may yield rapid results for anti-SARS-CoV-2 antibodies. The aim of this study was to evaluate the diagnostic accuracy of rapid antibody detection tests compared to a validated laboratory-based enzyme-linked immunosorbent assay (ELISA) and to investigate infections amongst healthcare workers (HCWs) after unprotected close contact to COVID-19 patients. Methods: Blood serum and whole blood of 130 participants were tested with NADAL® COVID-19 IgG/IgM Rapid Test and mö-screen 2019-NCOV Corona Virus Test against a validated ELISA test. Infection status was evaluated using real-time polymerase-chain-reaction.Results: Acute COVID-19 infection was detected in 2.4% of exposed HCWs. Antibody tests showed an overall frequency of IgG and IgM in 5.3%, with 1.6% asymptomatic infections. The NADAL® test showed a sensitivity (IgM/ IgG) of 100% (100%/ 100%), a specificity (IgM/ IgG) of 98.8% (97.6%/ 100 %), a PPV of 76.9% (57.1%/ 100%), an NPV of 100% (100%/ 100%), and a diagnostic accuracy of 98.8% (97.7%/ 100%). The mö-screen test had a sensitivity (IgM/IgG) of 90.9% (80%/ 100%), a specificity (IgM/IgG) of 98.8% (97.6%/ 100%), a PPV of 76.9% (57.1%/ 100%), an NPV of 99.6% (99.2%/ 100%), and a diagnostic accuracy of 98.5% (96.9%/ 100%). Conclusions: The frequency of COVID-19 infections in HCWs after unprotected close contact is higher than in the general population of a low-prevalence country. Both POC tests were useful for detecting IgG, but did not perform well for IgM, mainly due to false positive results.

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Evaluation of the diagnostic accuracy of a new point-of-care rapid test for SARS-CoV-2 virus detection

Journal of Translational Medicine ◽

10.1186/s12967-020-02651-y ◽

2020 ◽

Vol 18 (1) ◽

Author(s):

Leonardo Miscio ◽

Antonio Olivieri ◽

Francesco Labonia ◽

Gianfranco De Feo ◽

Paolo Chiodini ◽

...

Keyword(s):

Diagnostic Accuracy ◽

Real Time ◽

Real Time Pcr ◽

Point Of Care ◽

Virus Detection ◽

Rapid Test ◽

Reference Method ◽

Standard Of Care ◽

Easy Access ◽

Diagnostic Tools

Abstract Background The easy access to a quick diagnosis of coronavirus disease 2019 (COVID-19) is a key point to improve the management of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and to contain its spread. Up to now, laboratory real-time PCR is the standard of care, but requires a fully equipped laboratory and significant infrastructure. Consequently, new diagnostic tools are required. Methods In the present work, the diagnostic accuracy of the point-of-care rapid test "bKIT Virus Finder COVID-19" (Hyris Ltd) is evaluated by a retrospective and a prospective analysis on SARS CoV-2 samples previously assessed with an FDA “authorized for the emergency use—EUA” reference method. Descriptive statistics were used for the present study. Results Results obtained with the Hyris Kit are the same as that of standard laboratory-based real time PCR methods for all the analyzed samples. In addition, the Hyris Kit provides the test results in less than 2 h, a significantly shorter time compared to the reference methods, without the need of a fully equipped laboratory. Conclusions To conclude, the Hyris kit represents a promising tool to improve the health surveillance and to increase the capacity of SARS-CoV-2 testing.

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Diagnostic accuracy of a SARS-CoV-2 rapid test and optimal time for seropositivity according to the onset of symptoms

Cadernos de Saúde Pública ◽

10.1590/0102-311x00069921 ◽

2022 ◽

Vol 38 (1) ◽

Author(s):

Caroline Nespolo de David ◽

Fernanda Hammes Varela ◽

Ivaine Tais Sauthier Sartor ◽

Márcia Polese-Bonatto ◽

Ingrid Rodrigues Fernandes ◽

...

Keyword(s):

Diagnostic Accuracy ◽

Sensitivity And Specificity ◽

Clinical Symptoms ◽

Point Of Care ◽

Rapid Test ◽

Lateral Flow Immunoassay ◽

Optimal Time ◽

Rt Pcr ◽

Serological Tests ◽

Over Time

Point-of-care serological tests for SARS-CoV-2 have been used for COVID-19 diagnosis. However, their accuracy over time regarding the onset of symptoms is not fully understood. We aimed to assess the accuracy of a point-of-care lateral flow immunoassay (LFI). Subjects, aged over 18 years, presenting clinical symptoms suggestive of acute SARS-CoV-2 infection were tested once by both nasopharyngeal and oropharyngeal RT-PCR and LFI. The accuracy of LFI was assessed in periodic intervals of three days in relation to the onset of symptoms. The optimal cut-off point was defined as the number of days required to achieve the best sensitivity and specificity. This cut-off point was also used to compare LFI accuracy according to participants’ status: outpatient or hospitalized. In total, 959 patients were included, 379 (39.52%) tested positive for SARS-CoV-2 with RT-PCR, and 272 (28.36%) tested positive with LFI. LFI best performance was achieved after 10 days of the onset of symptoms, with sensitivity and specificity of 84.9% (95%CI: 79.8-89.1) and 94.4% (95%CI: 91.0-96.8), respectively. Although the specificity was similar (94.6% vs. 88.9%, p = 0.051), the sensitivity was higher in hospitalized patients than in outpatients (91.7% vs. 82.1%, p = 0.032) after 10 days of the onset of symptoms. Best sensitivity of point-of-care LFI was found 10 days after the onset of symptoms which may limit its use in acute care. Specificity remained high regardless of the number of days since the onset of symptoms.

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