The Delhi government instructed all health care facilities to carry out compulsory rapid antigen detection testing of patients with influenza like illness (ILI) symptoms, patients admitted with severe acute respiratory infection (SARI) and other high-risk individuals who visit their facilities.
All asymptomatic patients admitted or seeking admission of the following high-risk groups — patients undergoing chemotherapy, immunosuppressed patients [including HIV, patients with malignant disease, transplant patients, elderly patients [>65 years] with co-morbidities are included.
Rapid Antigen Test
Rapid diagnostic tests (RDT) detect the presence of viral proteins (antigens) expressed by the COVID-19 virus in a sample from the respiratory tract of a person. If the target antigen is present in sufficient concentrations in the sample, it will bind to specific antibodies fixed to a paper strip enclosed in a plastic casing and generate a visually detectable signal, typically within 30 minutes.
It is a rapid diagnostic test suitable for point-of-care testing that directly detects the presence or absence of an antigen. This distinguishes it from other medical tests that detect antibodies (antibody tests) or nucleic acid (nucleic acid tests), of either laboratory or point of care types. One inherent advantage of an antigen test over an antibody test (such as antibody-detecting rapid HIV tests) is that it can take time for the immune system to develop antibodies after infection begins, but the foreign antigen is present right away.