Formula showing tested POSITIVE for COVID-19

Hello,

Can anyone help me to create a formula for testing people for COVID-19 in quarantine facilities?

I have attached the excel spreadsheet showing what I want to calculate and display.

My idea is to display only POSITIVE cases in the cell 'Current Status - POSITIVE?' saying 'Yes' and highlight in RED.

I need a formula which reflects the latest tests and displays 'Yes' if people tested POSITIVE. Once the person has been tested POSITIVE needs two tests NEGATIVE to be allowed to go to home quarantine.

Thank You!