What is the difference between an hiv rna qualitative and quantitative test? what are there thresholds to detect the virus, and how accurate would the qualitative test be 9 weeks post pep, 13 weeks post exposure?

Qualitative test (commonly called nucleic acid test - NAT) is used as a screening test to identify, i.e. diagnose, HIV-infected individuals, such as screening possible blood donors, and quantitative test is mostly used for clinical management but it can be used for the diagnosis in certain situation. Negative results at week 9 post PEP and week 13 post exposure rule out HIV infection.