POZ Community Forums

HIV Prevention and Testing => Do I Have HIV? => Topic started by: Puzzled on February 19, 2009, 11:51:17 pm

Title: Unsure abt test data
Post by: Puzzled on February 19, 2009, 11:51:17 pm

About 5.5 weeks after a potential exposure, I got tested.  The test used was AxSYM HIV Ag/Ab combo.  Results were -ve, my value was 0.32 against mean of 0.35 and cut-off of 1.  More than 8 weeks after first test, I got tested again.  Same test kit.  Resutls were also -ve, but my value now showed 0.65 against mean of 0.63 and same cut-off of 1.  Nothing risky happened in between tests.  Should I be worried re near doubling of values?  Should I re-test after another 6 weeks or so?

Title: Re: Unsure abt test data
Post by: HIVworker on February 20, 2009, 01:51:54 am

The test is run with standards that are positive and standards that are negative. Your result is compared to the standards. The assay establishes a cut-off value - below which all results are deemed negative. Often the cut-off is normalized to one. A negative result can sometimes bounce around - as you really are in the noise of the assay. Doubling of the number doesn't indicate that there are antibodies in your blood that are doubling since the last test. It just means that below the cut-off of 1, your signal is bouncing around. If you had HIV antibodies, you would score higher than 1. If you don't, then you don't have HIV antibodies. A change in the signal doesn't indicate that you are 'starting to seroconvert' if that is your interpretation.

Regardless of that, a test at 12-13 weeks is considered conclusive.

R

Title: Re: Unsure abt test data
Post by: Puzzled on February 20, 2009, 03:17:25 am

Not sure I understand about -ve results bouncing around.  Does the same happen with +ve results? Pls elaborate.  Also, I read somewhere that the instructions provided by the test manufacturer (Abbott) include retesting if the values are between 0.9 and 1.0.  That suggests the actual -ve value means something.

Title: Re: Unsure abt test data
Post by: RapidRod on February 20, 2009, 04:38:12 am

You were explain the process in detail. If you test was less than 1 and you test at 3 months post exposure then you are conclusively negative.

Title: Re: Unsure abt test data
Post by: Ann on February 20, 2009, 05:53:50 am

Puzzled,

What was your "potential exposure"? Unless it was unprotected anal or vaginal intercourse, you're likely worrying over nothing.

Ann

Title: Re: Unsure abt test data
Post by: HIVworker on February 20, 2009, 09:37:42 am

I agree with Ann here. This might be worrying about nothing. What was the risk?

Also, if you test very close to the cutoff it's indeterminate and they do a Western blot. You are nowhere near it.