Manx Care says it doesn't know how many people test positive for HIV on the Island.
A freedom of information request asked for annual figures for the number of tests taken and the number which turned out to be positive since 2015.
However, in its reply Manx Care said it doesn't hold the information.
It added its pathology directorate carries out around 1,200 HIV tests each year but most are screens for the blood donor service.
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