COVID-19 Test

We belief for travel purposes and for individual or community surveillance including testing in schools and for establishment monitoring this combined approach would be ideal. This approach can work in community settings to assist in understanding of Covid-19 spread and may help not only the individual but the decision makers. WHO also recommended such a combined approach and it is called orthogonal testing which in real terms means testing a patient’s samples with two tests, each with unique design characteristics.

The advice from FDA in USA is similar: It is important to minimize false positive test results by choosing an assay (test) with high specificity and by testing populations and individuals with an elevated likelihood of previous exposure to SARS-CoV-2. Alternatively, an orthogonal testing algorithm (i.e., employing two independent tests in sequence when the first test yields a positive result) can be used when the expected positive predictive value of a single test is low. So, our clinical approach is the same as here. If one test is positive for Covid-19 antigen or antibodies (anti SARS-CoV-19), it is a good idea to do a second test. Here we are doing several tests at the same time to understand and explain the findings of our tests. Especially if clinically it is considered that the person’s history of illness is not combatable with Covid-19 illness. If it is the other way around- meaning the test is unexpectedly positive then orthogonal testing can help. Certainly, the patient who has any positive antigen test MUST be considered as positive and as having the virus. Such a person might like to repeat the test. Here in our testing methodology we have implemented the orthogonal testing methodology from the onset. We are doing several tests at the same time to understand and explain the findings of our tests.

We are addressing orthogonal testing robustly when it comes to antibody testing. If the first test is a point of care (finger-prick cassette) test, or the serological test like Roche/Abbott antibody test then a second test like Sarsplex is well placed as the diagnostic test. Sarsplex is an ELISA based test and is considered the gold standard for antibody testing. Clinical history and test results should be in concordance. But if the test is negative and clinical history is convincing for Covid-19 then we might have to explain the possibility of a false negative test and always consider doing a diagnostic test like the Sarsplex. We are expected to be honest with the patient and discuss the findings. We will always do so .Finger-prick rapid blood test or Abbott/Roche antibody test plus Sarsplex test can be a good clinical tool which we are going to practice.

As Covid-19 is a notifiable disease by law even suspected Covid-19 must be notified.