The anal Pap test has not been studied enough to know how often it should be done, or if it actually reduces the risk of anal cancer by catching AIN early.  
The anal Pap test has not been studied enough to know how often it should be done. Some experts recommend that the test be done in at-risk people who are: >Annually HIV-positive. >every 2 to 3 years in at-risk people who are HIV-negative.  