Evaluation of the Truvian Easy Check COVID-19 IgM/IgG Lateral Flow Device for Rapid Anti-SARS-CoV-2 Antibody Detection

Clarence W. Chan, MD, PhD; Sajid Shahul, MD; Cheyenne Coleman, MT(ASCP); Vera Tesic, MD; Kyle Parker, MD; Kiang-Teck J. Yeo, PhD


Am J Clin Pathol. 2021;155(2):286-295. 

In This Article

Abstract and Introduction


Objectives: To evaluate the analytical and clinical performance of the Truvian Easy Check coronavirus disease 2019 (COVID-19) IgM/IgG anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody test.

Serologic assays have become increasingly available for surveillance through the Food and Drug Administration emergency use authorization in the ongoing COVID-19 global pandemic. However, widespread application of serologic assays has been curbed by reports of faulty or inaccurate tests. Therefore, rapid COVID-19 antibody tests need to be thoroughly validated prior to their implementation.

Methods: The Easy Check device was analytically evaluated and its performance was compared with the Roche Elecsys anti-SARS-CoV-2 antibody assay. The test was further characterized for cross-reactivity using sera obtained from patients infected by other viruses. Clinical performance was analyzed with polymerase chain reaction-confirmed samples and a 2015 prepandemic reference sample set.

Results: The Easy Check device showed excellent analytical performance and compares well with the Roche Elecsys antibody assay, with an overall concordance of 98.6%. Clinical performance showed a sensitivity of 96.6%, a specificity of 98.2%, and an overall accuracy of 98.1%.

Conclusions: The Easy Check device is a simple, reliable, and rapid test for detection of SARS-CoV-2 seropositivity, and its performance compares favorably against the automated Roche Elecsys antibody assay.


Newly developed laboratory assays have become increasingly available worldwide to help guide both clinical management and public health measures in the ongoing coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).[1,2] Although the rapid development of many serologic assays has sought to address the paucity of information on the epidemiologic spread of the virus, recent reports of potential inaccuracy or inapplicability have called into question their reliability as dependable diagnostic tools in certain clinical settings.[3–5] The cause of unsatisfactory assay performance is typically multifactorial; however, withdrawal of usage by the US Food and Drug Administration (FDA) includes noncompliance of Emergency Use Authorization (EUA) requirements and delayed validation studies.[6–9] In response to such concerns, the FDA made several updates (March 16, May 4, and May 11 of 2020) to tighten validation guidelines in its initial policy statement on February 29, 2020, for manufacturers developing antibody-based tests against SARS-CoV-2.

Quantitative and qualitative reverse transcription polymerase chain reaction (RT-PCR) remain the gold standard testing for diagnosing active infection by SARS-CoV-2 and is applied by direct detection and amplification of viral genetic material.[10] In contrast, serologic assays are indirect tests that detect the presence of IgM, IgG, and total antibodies in patient plasma or sera, which typically develop several weeks after initial infection.[11–13] Although IgM, IgG, and total antibody levels are thought to peak after 2 to 3 weeks, 3 to 6 weeks, and 2 to 3 weeks, respectively,[14–17] both IgM and IgG levels can vary considerably so most serologic assays aim to detect both IgM and IgG simultaneously for improved sensitivity.[18]

The Easy Check is a rapid diagnostic test that utilizes an immunochromatographic-based, lateral flow platform to detect both IgM and IgG antibodies against SARS-CoV-2 applied in a stand-alone device format. Whereas RT-PCR requires at least several to 24 hours of processing and turnaround time, lateral flow devices provide results rapidly to allow for near-immediate assessment of a patient's exposure history.[19] Therefore, particularly as large segments of the US population remain undertested and with the number of COVID-19 cases still continuing to rise several months after the first confirmed US case in January 2020,[20] availability of the Easy Check device will help address current gaps by providing real-time information of the seroconversion status of individuals who have been infected by SARS-CoV-2.[21–23]

In this study, the Easy Check was evaluated analytically and clinically and the basis of its technology is briefly described. The clinical performance of the Easy Check was validated using prepandemic, SARS-CoV-2-negative, and SARS-CoV-2-positive, PCR-confirmed patient samples and compared against the performance of the Roche Elecsys anti-SARS-CoV-2 antibody assay.[24,25] The Easy Check demonstrated excellent analytical performance, high sensitivity and specificity, as well as minimal cross-reactivity against plasma or sera obtained from patients infected by other viruses, and is therefore a reliable modality for widespread and rapid serologic testing of SARS-CoV-2 infection.