Dried blood is less contagious because HIV quickly loses its ability to infect when dried - some sources report that after the blood dries, the concentration of HIV decreases 10 times every 9 hours. In my opinion, the probability of infection as a result of contact with traces of dried 3-day-old blood is negligible. I enclose helpful materials: https://www.gdziepolek.pl/artykuly/co-warto-wiedziec-o-hiv-i-aids https://www.gdziepolek.pl/kategorie/leki-na-hiv In pharmacies, there are tests available for self-administration at home for HIV, e.g.: https://www.gdziepolek.pl/produkty/114944/test-na-hiv-do-samokontroli-simplitude-byme-domowy-test/apteki On the attached page you can compare the prices of the test in online pharmacies and order it with home delivery.