Accuracy of Rapid Point-of-Care Antibody Test in patients with suspected or confirmed COVID-19
Authors: Vancheeswaran Rama , Willcox Merlin L , Stuart Beth , Knight Matthew , Kandil Hala , Barlow Andrew , Patel Mayon Haresh , Stockham Jade , O’Neill Aisling , Clark Tristan W , Wilkinson Tom , Little Paul , Francis Nick , Griffiths Gareth , Moore Michael 
Published: November 2020

Objectives

To assess the real-world diagnostic accuracy of the Livzon point-of-care rapid test for antibodies to SARS-COV-2

Design

Prospective cohort study

Setting

District general hospital in England

Participants

173 Patients and 224 hospital staff with a history of COVID-19 symptoms, and who underwent PCR and/or reference antibody testing for COVID-19.

Interventions

The Livzon point-of-care (POC) lateral flow immunoassay rapid antibody test (IgM and IgG) was conducted at least 7 days after onset of symptoms and compared to the composite reference standard of PCR for SARS-COV-2 plus reference laboratory testing for antibodies to SARS-COV-2. The SARS-CoV-2 RT-PCR was tested using the available molecular technology during the study time (PHE laboratories, GeneXpert®system Xpert, Xpress SARS-CoV-2 and Source bioscience laboratory). All molecular platforms/assays were PHE/NHSE approved. The reference antibody test was the Elecsys Anti-SARS-CoV-2 assay (Roche diagnostics GmBH).

Main outcome measures

Sensitivity and specificity of the rapid antibody test

Results

The reference antibody test was positive in 190/268 (70.9%) of participants with a history of symptoms suggestive of COVID-19; in the majority (n=312) the POC test was taken 35 days or more after onset of symptoms. The POC antibody test had an overall sensitivity of 90.1% (292/328, 95% CI 86.3 – 93.1) and specificity of 100% (68/68, 95% CI 94.7 - 100) for confirming prior SARS-CoV-2 infection when compared to the composite reference standard. Sensitivity was 97.8% (89/92, 95% CI 92.3% to 99.7%) in participants who had been admitted to hospital and 84.4% (124/147, 95% CI 77.5% to 89.8%) in those with milder illness who had never been seen in hospital.

Conclusions

The Livzon point-of-care antibody test had comparable sensitivity and specificity to the reference laboratory antibody test, so could be used in clinical settings to support decision-making about patients presenting with more than 10 days of symptoms of COVID-19.

What is already known on this topic

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Presence of IgG and IgM antibodies to SARS-COV-2 indicates that the person was infected at least 7 days previously and is usually no longer infectious.

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Rapid point-of-care tests for antibodies to SARS-COV-2 are widely available, cheap and easy to use

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Preliminary evaluations suggested that rapid antibody tests may have insufficient accuracy to be useful for testing individual patients.

What this study adds

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The rapid point-of-care test for antibodies to SARS-COV-2 was 90.1% sensitive and 100% specific compared to reference standards for prior infection with COVID-19.

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This is comparable to reference antibody tests

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The point-of-care test evaluated in this study could be used to support clinical decision-making in real time, for patients presenting with symptoms of possible COVID-19 with at least 10 days of symptoms.