Welcome back to the forum. I’ll be glad to comment.  Your test results are conclusive. In general, while we prefer laboratory based tests performed on blood drawn from a vein, the Abbott Determine test however is highly reliable and your results should be believed, particularly if you’ve now done the test twice. The combination of your multiple negative Oraquick tests, your negative ChemBio test, and now two negative Abbott Determine fourth generation tests provide conclusive evidence that you were not infected with HIV. I would have no concerns and see no reason for further testing.---

So there is no way that someone who is administering the test could measure the blood or buffer fluid incorrectlyand invalidate the test? as long as there is a control line, the test is valid?  Thank you

I understand how concerning an exposure to a person with known HIV can be, however it is time for you to except your results. You have had multiple tests using three different types of tests, each of which has its own controls built into the test. Believe the results. The tests were not done incorrectly. You did not acquire HIV from your exposure of concern. EWH---

Thank you for your patience Dr Hook. Forgive me for restating the question but knowing that the test mechanism is idiot proof will help me accept the results and move on with my life. I just can't explain the severe symptoms that I had from these encounters some still persist months later. So just for clarification do the internal controls for this test pretty much eliminate the possibility of human error? There is no way that insufficient volume of blood specimen could result in  a false negative test? If there was not enough blood then there would be no control line and the test would be clearly invalid? I am just asking because it seemed like the drop of blood just barely filled up the pad. i assume that the test is designed so that if the measurements are not precise enough, the test would not develop a control line?

Sigh. This is a repetitive question and the answer is not going to change. You have repeated your test twice, it has highly reliable internal controls, and cannot be messed up. You need to believe your test results. If you are experiencing symptoms that are troublesome to you my strong advice is to work with your doctor to see their cars being confident that they are not due to HIV.---