• Being 100% specificity-compliant, Ortho’sVITROS^®Anti-SARS-CoV-2 Total and IgG tests can help identify, with great confidence, previously exposed individuals who have developed antibodies to SARS-CoV-2
• When coupled with a molecular test that detects active infection, it can monitor the progression of the disease by measuring when antibodies appear in the blood

Study results show that even with 97% specificity, there is a chance of getting 30 false positive results out of 1,000 and with 99.6%, 4 false positive results out of 1,000. Only with 100% specificity can one be fully confident that the antibody positive test result is a true positive, such as with the one developed and launched recently by Ortho Clinical Diagnostics.

Why 100% specificity is vital

Unlike many commercially available antibody test kits, Ortho’s high-throughput, automated VITROS^® Anti-SARS-CoV-2 antibody tests are highly reliable and have demonstrated 100% specificity in assay validation studies. The tests can help identify with high accuracy a previously infected patient who can donate antibody-containing plasma to treat severe COVID-19 patients. This is important because any inaccurate test result could lead to a plasma therapy without antibodies to SARS-CoV-2, the active ingredients in the convalescent plasma therapy.

Both VITROS^® Anti-SARS-CoV-2 antibody tests target the S1 subunit of the Spike (S) protein of SARS-CoV-2. The virus uses the S1 protein to bind to the angiotensin-converting enzyme 2 (ACE2) receptor to facilitate viral entry and infection.  Antibodies that can bind to S1 and block S1-ACE2 interaction can inhibit viral infection, which are called neutralizing antibodies.  The VITROS^® Anti-SARS-CoV-2 antibody tests can detect neutralizing antibodies that bind to the S1 protein.

Ortho’s 100% specificity-compliant antibody assay for Covid-19 testing — the VITROS^® Immunodiagnostic Products Anti-SARS-CoV-2 Total and IgG Reagent Packs and Calibrators — have now been included in the updated list of approved Rapid/ CLIA/ ELISA kits the Central Drugs Standard Control Organization (CDSCO), under the Ministry of Health and Family Welfare, GoI. (*No other company has 100% specificity).

New CDC guidelines

The recent guidelines from the Centre for Disease Control and Prevention (CDC) for Covid-19 antibody testing emphasizes on the serological methods/antibody testing towards monitoring and responding to the Covid-19 pandemic.

Antibodies most commonly become detectable 1-3 weeks after symptom onset, at which time evidence suggests that infectiousness is, possibly, greatly decreased and that some degree of immunity from future infection has developed.

Recommended testing strategies

The utility of laboratory tests depends on the sensitivity and specificity of the assays. Also, the predictive values of a test should be considered because these values affect the overall outcome of testing.

• Positive predictive value is the probability that individuals with positive test results are truly antibody-positive.
• Negative predictive value is the probability that individuals with negative test results are truly antibody-negative.
• Positive and negative predictive values are determined by the percentage of truly antibody-positive individuals in the tested population (prevalence, pre-test probability) and the sensitivity and specificity of the test.

In the current pandemic, maximizing specificity, and thus positive predictive value, in a serologic algorithm is preferred in most instances, since the overall prevalence of antibodies in most populations is, possibly, low. Choosing a test with a very high specificity, perhaps 99.5% or greater, will yield a high positive predictive value in populations tested with prevalence >5%.

High throughput

• The VITROS^®analyzers (i.e. instruments) from Ortho can run up to 150 of these critical tests/hour
• The COVID-19 antibody tests can be run on all Ortho’s flagship laboratory analyzers, the VITROS^® XT 7600 Integrated System, the VITROS^® 3600 Immunodiagnostic System and the VITROS^® 5600 Integrated System

Production plans

• Ortho will be in full production mode in the coming weeks
• It plans to manufacture several million SARS-CoV-2 antibody tests over the next month

About Ortho Clinical Diagnostics

• Ortho Clinical Diagnostics is a global leader of in vitro diagnostics, dedicated to saving and improving lives through innovative laboratory testing and blood-typing solutions- for the past 3 decades
• Ortho is powered by Ortho Care™, its global, award-winning, holistic approach to service

‘Saving lives, saving economy’

‘The Covid-19 pandemic continues to impact individuals, communities and families worldwide. Ortho is proud to be working towards large-scale solutions that will help people return to work, reducing the strain on both employees and the economy as a whole. Our focus on improving patients’ lives through diagnostics led us to developing this test rapidly’— Chris Smith, CEO, Ortho Clinical Diagnostics, USA

‘Long track record’

‘Our test kits have been approved by the CE and the U.S. FDA (EUA). They are widely used by prestigious hospitals and labs, such as Quest Labs, in the US. Our instruments are used for HIV, HBsAg and HCV screening across the world and the technology is being used for blood screening for more than 25 years in prestigious hospitals and blood banks in India and other SAARC countries’— Anand Pande, V-P, A-Pac, Ortho Clinical Diagnostics