Dear Doctor I Took An HIV Test Which Is The

Dear Doctor I took an HIV test which is the s-HIV1- HIV2 Ab IgG - 2 TEST ELFA with the result of the first one (env HIV1 and HIv2, core HIV1) NEGATIVE and ELFA ( ag p 24 and gp41 env HIV1-gp36 env HIV2 ) NEGATIVE. this result is 4.5 weeks after the risky encounter. How reliable is the test result? thanks