How did Rock Lee pass the academy test? I stumbled over this question on Facebook. I was wondering how Rock Lee got out of the academy and why did they let him leave?
One does not need to use Henge no Jutsu in order to graduate the ninja academy. Promotion throughout the entire series is never dependent upon a certain technique, but rather the capabilities of that shinobi determined by the Hokage and village elders.

Take a look at the Chuunin selection exam. Shikamaru received the only promotion yet there was no way he could have won the entire tournament.

While Lee could never use ninjutsu nor genjutsu, he was able to have very good technique with taijutsu and that allowed him to graduate. Lee just uses his chakra in a different way, but that doesn't make him any less of a ninja. 

Same with Shino for that matter. Shino lets his bugs eat his chakra and then he can command them. So instead of making a kage bunshin, Shino uses a lot of bugs to form a clone. 

Because every shinobi specializes in different areas, there is no set requirements in order to be promoted. The decision comes from the Hokage and the elders for Chuunin and above. For the academy, the instructor decides when the child is ready to be a Genin.