Thank you for your inquiry. From what gather from your question, you were asking about the differences in conclusive test result information between our guideline references, and your own.
Due to the nature of our online/anonymous services, we are not always provided with all the required information to make completely accurate assumptions regarding each users scenario. For this reason, we may provide a generalized Recommendation that is inclusive to HIV screening methods that have window periods up to 12 weeks post exposure.
You are correct in your assumption that each test has a unique window period. For example, the Antigen/Antibody Test is able to detect the presence of HIV from approximately 23-90 days post exposure (1). Others, such as the Rapid self-test can provide a conclusive result anywhere between 6 to 12 weeks. Our recommendations for retesting are based on the maximum time frame that would cover all tests available for detecting HIV (2).
Although many tests can be considered conclusive well before 12 weeks, we always Recommend to our users that they receive follow up testing at 12 weeks or later for completely conclusive results. This is also our way of avoiding the possibility of false positives or false negatives (which are extremely unlikely, yet do happen in certain circumstances).
Below we have linked some of the resources that we use when attempting to provide accurate, up to date, and scientifically proven information regarding HIV transmission.
All the best,
AIDS Vancouver Online/Helpline, Cody