Question 1042368
=======Test +========Test-=======Total
HIV+----------------------------------------1000
HIV-
Total-------------------------------------1,000,000
You know this first, and then you can put in the 99.9% sensitivity and specificity.

=======Test +========Test-=======Total
HIV+-----999--------------1--------------1000
HIV------999------------998001---------999000
Total-----1998----------998002---------1,000,000

The positive predictive value is 50%, 999/1998
The negative predictive value is 998001/998002 or 99.999+%
The number of people who test positive and are disease free is 999.