The Bioscientia laboratories now offer a test for the detection of IgA and IgG antibodies against SARS-CoV-2. The test is performed from serum, heparin or EDTA plasma. The Robert Koch Institue (RKI) does not yet have a case definition that could serve as a decision criterion for an indication for testing. Therefore, we recommend the request of antibody detection to confirm a fresh SARS-CoV-2 infection.
All test manufacturers we are in contact with report high production capacities. They expect sufficient supply capacity to meet the upcoming demand in German laboratories from April 20. Samples that you send us by then will be carefully archived and examined as soon as they are ready for testing. Alternatively, you can send us fresh sera from the week after Easter.
Unless there are pandemic-related bottlenecks in the supply of test components, samples will be processed on the same day.
Notes on the interpretation of the results:
As expected, first studies with sera from patients with proven SARS-CoV-2 infection and various test systems have shown that detectable antibodies develop in the course of an infection after 1-4 weeks.
The antibody tests primarily serve to diagnose a SARS-CoV-2 infection and support the direct detection of the pathogen.
For the frequently desired use, namely the confirmation of an immunity against SARS-CoV-2, there are currently not yet sufficient data available.
Cross-reactivities are described for the systems tested by us against other beta-corona viruses such as OC-43 and SARS-CoV-1. The test manufacturer states the specificity for IgG detection at 98.5%, for IgA detection at 92.5%. Furthermore, the IgA test showed 12.7% positive results in a blood donor collective collected before the pandemic.
For these reasons, we are initially concentrating our test capacities on the detection of antibodies in confirmed PCR-positive cases. This can, for example, support the production of immunotherapeutic drugs (plasma donations).