The conclusions are a bit alarming. Sexually active gay men in an STD clinic were tested for HIV RNA, which is a test for the virus itself, as opposed to most tests, which look for antibodies against the virus.
In these sexually active men, 10% of those who tested negative for antibodies against HIV were positive for RNA tests. This means that they were recently infected, highly infectious, but had a recent negative HIV test.
New HIV tests which use both RNA and antibodies are coming, very soon, but for now, if you meet men on line, a negative test could have an error rate of 10%.
For sexually active gay men, false negatives are a real issue.