Has anyone come across cards, or other devices,  on which one can dry a spot
of blood and send it to a lab for analysis. I am not interested in the
Guthrie type cards as I would like to recover a protein from the card and
assay it. So I am looking for a card on which the protein does not denature
and from which it can be eluted. There were PSA and HIV (antibody) tests
available a few years ago and the user put a spot of blood on them and sent
them to a lab for analysis and the result was sent back to them. I just want
the cards and do not want to pay for the test as I have my own test.

Any ideas on who makes such cards.

Thanks for your help.

Bob