Pls help! VL results very confusing! Anxious

Question

Hello, Thank you for taking the time and reading my post.

I tested positive in March 2016 with an extremely high viral load of 586654 copies/ml. I was placed on viraday - up till now.

It took me some time to become undetectable. I became undetectable in November 2016.

Now after six months, I retested my viral load to keep track. Please consider all the details below - i was emailed the results:

Test: HIV1 RNA Viral Load

Method: Quantitative Real-Time PCR This assay detectd the subtypes of HIV1 groups M-O.

Platform: GeneXpert system

Result: Negative

Comment: HIV1 RNA negative. There is no indication of HIV1 viremia.

Linear range of the assay: 40 to 10 000 000 copies/ml.

The results are so confusing. How come the result is negative and not undetectable? In November the result said undetectable and now the result says negative. How come? Shouldnt it be undetectable? Shouldnt it be negative when the viral load is simply 0 or there is no virus in my blood? I sent my results to my Dr but he is out of town and hasnt replied yet and I cant wait. I am so anxious. Hope you can help me understand my test results. Thank you!

Answer

I assume the first test was also performed using this assay and not another HIV viral load assay. The language used to report results that are below the detectable range has resulted in a lot of confusion among patients and providers alike. As you state, the quantitative range for this assay is 40 to 10 million copies/ml. That means nothing below 40 copies can be quantified. However, there is a certain range between 1 to 40 copies/mL where viral load could be detected but not quantified, or further below that arbitrary copy number, not detected. It is likely in this case that negative is the same as undetected or undetectable.