Allow me to post a similar question again.I visted the usa cdc website,and it shows that,6 months is conclusive,
the link is:http://www.cdc.gov/hiv/topics/testing/resources/qa/be_tested.htm
Some one kind in this forum answered me that,it was changed to 3 omnths in 2004.
But in USA,every state has its own cdc,they have differnet guidelines.And,what is the window period of the national cdc of USA,but not the window period recommended by a certain state's cdc.
I am waiting for your help, please.