Keep in mind that there can be "false positive" test results (i.e., testing that picks up antibodies that are similar to those seen in HIV but are not). Thus, the general rule is that a positive ELISA screening test needs to be followed by a second test, known as a Western Blot.
If the ELISA is reactive (positive) but the Western Blot is negative, the person is said to be HIV negative and the first test was a false positive result.
If both come back as reactive/positive, then the next step is to make an appointment with an Infectious Disease specialist who will likely order further tests to determine if/when medication should be started.
Interestingly, there often is no need to start medication in early stage HIV. Keep in mind that any medication does not cure the disease but rather works to slow/avoid the progression of HIV to the last stage of the disease (AIDS).