When you are born you had a prick in your heel and you put the blood spot on a card called a Guthrie card. You let the card dry and then you can stick the card in the post. In terms of coronavirus, it will be dead in a couple of days max and it is not going to escape the enveloped to infect the postie
A blood spot is about 50-75 microlitres in volume. When the spot is dry the contents are relatively stable and you can extract the antibodies in the blood and measure it for presence of antibodies against the COVID-19-related virus. You don’t need much fluid for the test. You don’t have to go anywhere and a blood spot kit can be popped in the post. A lancet gives you a little skin prick and it is easy peasy to do.
DrAngry says there is also another easy technology, which is a sponge on a stick and it sucks the blood into the sponge and is easier to handle, if we get some cash to buy them it wil be a nice choice to have