Accuracy of DUO at 27 days

[GuiltyHusband]

Dear Doctor,

A week ago I engaged in unprotected cunnilingus with a CSW in Shanghai.  I am concerned as the gum beside my buck tooth bleeds when I brush vigorously.  I plan to get a Duo test done, but due to my business schedule, I only have the chance to schedule one on 27th day of exposure.  As DUO is mentioned by other experts to be conclusive at 4 weeks, I'm wondering if this 1 day difference would make a significant impact on the accuracy of the test result.  I.e. if it is negative at 27th day, should that be conclusive to put my worries to rest?

Thanks so much.

Best Regards

[Dr Sean Cummings]

Hello

I'm sure you are fine. Cunninlingus represents an extraordinarily low risk in terms of HIV contraction. The DUO test is exceptionally accurate at 28 days and will be perhaps a 0.1% off the day before.

The two combined - extraordinarily low risk of acquisition and exceptionally accurate test - indicates that you are HIV negative,

kind regards, Sean

[GuiltyHusband]

Thanks for the quick advice.  In case, DUO is not available (I inquired to the hospital via phone.) when I get there and they only have a 4Gen antibody test, would a negative be also sufficiently conclusive.

Also, I believe that clinic tests for Syphilis as a mandatory standard along with HIV.  Is the window period too small for an accurate syphilis detection (i.e. I should test that separately on a later date.)