The Science Behind
Drop™ COVID-19 antibody test is useful for the detection of individuals who may have developed IgG/IgM antibodies and presumed immunity to the SARS-CoV-2 virus.
Using a small blood sample, the Drop™ COVID-19 antibody test helps to detect recent past exposure to the SARS-CoV-2 virus by measuring the immune response to the infection. This is done by identifying the presence of IgM and IgG antibodies in an individual’s blood.
An immune response can be detected approximately 2 weeks after infection in asymptomatic individuals and approximately 8-10 days after the onset of symptoms for those who have experienced fever and coughing (based on current science to date, April 2020). This test cannot detect an infection at early stages during the first 5 days after the incubation period.
It is unclear how long IgG antibodies are detectable months or years after an individual becomes infected with the SARS-CoV-2 virus. Hence, we cannot yet draw the conclusion that long-term immunity against COVID-19 exists with the presence of IgG antibodies today.
Once the collection device with a dried blood sample arrives at the CoreMedica Lab, the dried blood sample is reconstituted by adding a buffered solution. Next the sample processed in a specialized machine using the ELISA Method.
Results are uploaded to a secure HIPPA compliant portal and the patient will be notified to review your report.
The HemaSpot-SE™ design provides rapid separation of blood serum with no cell hemolysis. The dry blood spot is then reconstituted using a buffer at the lab and the serum is tested using the ELISA methodology.
Traditionally, one SST blood tube needs to be drawn in person at a lab where the red cells are separated from the serum using a centrifuge. Only a few drops of serum are then tested using the ELISA methodology.
RAPID Serologic Tests
At the moment, the true accuracy of RAPID serologic tests for SARS-CoV-2 is uncertain. In time, this may change as technology improves. The Food and Drug Administration (FDA) has granted an emergency use authorization (EUA) for a few antibody tests, the first one from Cellex, made in China. This test is 93.8% sensitive and 96.4% specific in testing on only 128 samples from Chinese COVID-19 patients confirmed by molecular genetic testing using RT-PCR. Other tests show a sensitivity rate as low as 80% (false negative of 20%).
The EUA allows a company to market unapproved diagnostic and therapeutic products during a declared emergency. According to “Policy D,” serologic tests for SARS-CoV-2 can be marketed and sold to clinical labs and hospitals as long as manufacturers have generated some level of validation data, even though the FDA has not reviewed the data.
ELISA Remains the Gold Standard
In contrast to the gold standard ELISA methodology used by CoreMedica’s Drop™ COVID-19 Antibody Test, these ‘Rapid’ Screening tests in the open market developed and manufactured outside of North America (and mainly from China) use a LFIA (lateral flow immunoassay) methodology.
Measured against the ELISA test, the LFIA method is far less sensitive (false negative rate), meaning that it may miss up to 20% or 1:4 people who actually may have antibodies are incorrectly told they don’t have any antibodies against COVID-19. As well, the LIFA is not completely specific (false positive rate), and inaccurately advises about 5% of those tested that they are immune when they, in fact, don’t have any antibodies against COVID-19.
Challenges of COVID-19 Testing
Dr. Sanjay Gupta, Chief Medica Correspondent, CNN
Canadian Antibody Testing Report
Avis Favaro, Medical Correspondent, CTV National News
The DropTM COVID-19 antibody test performed by CoreMedica, established in 2020 in Lee’s Summit, Missouri, USA, specializes in minimally invasive testing. CoreMedica is a CLIA licensed and CAP Accredited Laboratory.
CoreMedica’s SARS-CoV-2 virus IgG and IgM antibody test is under the regulatory jurisdiction of the U.S. Department of Health and Human Services who enforces the Clinical Laboratory Improvement Amendments (CLIA) program. Any organization must have a CLIA certificate in order to provide clinical laboratory services in the United States. The CLIA program is administrated by the Centers of Medicare and Medicaid (CMS), the Centers for Disease Control and Prevention (CDC), and the Food and Drug Administration (FDA). PEUA200459
The ELISA testing methodology used by CoreMedica for antibodies detection does not require Health Canada approval because the test is completed using a standardized laboratory technique in a licensed laboratory in the United States and ordered by a licensed Canadian physician.
Dry Blood Spot Collection Device
The HemaSpot-SE Blood Collection and Transport Device is listed with the FDA as a Class I device (general controls), Product Code: NNK, and under 21 CFR 864.3250. This device is exempt from the premarket notification and does not require FDA approval.
In Canada, CoreMedica has filed their HemaSpot-SE™ Collection Device with Health Canada and are awaiting approval that this device meets the health and safety standards of Health Canada to collect blood drops. Therefore, blood collection using the HemaSpot-SE™ Collection Device in Canada will be performed under physician supervision until this device is approved by Health Canada.