Background and Method

About Clinical Trials

Serological tests are crucial tools for assessments of SARS-CoV-2 exposure, infection and potential immunity. Their appropriate use and interpretation require accurate assay performance data. We conducted an evaluation of 10 lateral flow assays (LFAs) and two ELISAs to detect anti-SARS- CoV-2 antibodies. The specimen set comprised 130 plasma or serum samples from 80 symptomatic SARSCoV-2 RT-PCR-positive individuals; 108 pre-COVID-19 negative controls; and 52 recent samples from individuals who underwent respiratory viral testing but were not diagnosed with Coronavirus Disease 2019 (COVID-19). Samples were blinded and LFA results were interpreted by two independent readers, using a standardized intensity scoring system. 



Among specimens from SARS-CoV-2 RT-PCR-positive individuals, the percent seropositive increased with time interval, peaking at 81.8-100.0% in samples taken >20 days after symptom onset. Test specificity ranged from 84.3-100.0% in pre-COVID-19 specimens. Specificity was higher when weak LFA bands were considered negative, but this decreased sensitivity. IgM detection was more variable than IgG, and detection was highest when IgM and IgG results were combined. Agreement between ELISAs and LFAs ranged from 75.8-94.8%. No consistent cross-reactivity was observed.



Our evaluation showed heterogeneous assay performance. Reader training is key to reliable LFA performance, and can be tailored for survey goals. Informed use of serology will require evaluations covering the full spectrum of SARS-CoV-2 infections, from asymptomatic and mild infection to severe disease, and later convalescence. Well-designed studies to elucidate the mechanisms and serological correlates of protective immunity will be crucial to guide rational clinical and public health policies. 


High Sensitivity

Sure API Covid-Rapid will correctly catch more than 50% of asymptomatic infections in week one. By screening in mass numbers, this will allow us to quarantine people who otherwise would have been missed. Don’t look at it as missing 50% of cases, but finding 50% of previously undiagnosed cases, and stopping all the downstream transmission of people that they would have otherwise infShow More


Highest Specificity

Sure API Covid-Rapid is the only test with zero false positives. If somebody tests positive, they have COVID19. Period. 


Zero cross reactivity. 

Sure API Covid-Rapid will not show any false positives for other viruses. Positive means you have COVID19. Period. 


No complaints or comments about Sure API Covid-Rapid


Highest agreement. 

Between two readers looking at tests, they agreed over 99% of the time, the highest in class. This means the lines are clear, concise and anyone can read them.