Corona tests. To clear up confusion.

PCR test | Tests for CURRENT INFECTION by detecting virus genetic material.

Antigen test | Tests for CURRENT INFECTION by detecting virus protein.

Antibody test | Tests for HISTORIC INFECTION by detecting human immune system protein.

PCR test | Nasal swab. Is viral genetic material on the swab? High throughout, sensitive. Superior to antigen test.

Antibody test | Blood spot ‘home kit’. Does your blood contain proteins that would only be there if you’d had the virus? Easy to administer, not yet robust.

PCR test | Viral DNA will not be present if you have cleared the virus. Therefore, it cannot detect historic infection.

Antibody test | It takes a few weeks for your body to produce enough protein to be detectable in a blood spot. Therefore, it cannot detect current infection.

Some biology.

Antigen | A protein recognised as ‘foreign’ (say, one coating a virus) and triggering an immune response.

Antibody | A protein called an immunoglobulin (Ig) that forms part of a body’s immune response. They come in several types. Hence you’ll hear IgG, IgM...

Antigens and antibodies stick together.

You can detect an antigen by trying to bind the antibody that developed to fight it.

You can detect an antibody by trying to bind the antigen it fights.

Yin yang.