The CDC recommends that everyone between the ages of 13 and 64 get tested at least once as part of routine health care. For those with specific risk factors, the recommendation is testing once a year.*
In 2014, the CDC published a new HIV testing algorithm. The 2018 update of the algorithm is shown below and can be found on the CDC website at:
Note that if a fifth generation assay is used, differentiation of all three HIV analyte markers (antigen, HIV-1, and HIV-2 antibodies) occurs in the first step.
*Reference: