good evening sir, i'm a 23 yr old female medical graduate from india, during my internship i had hiv infected neddle prick injury,this happened was a yr ago. i had a pcr done then, it came "not positive". in one of the medicine text books, i read that there is a window period for pcr(12) days. igot the pcr done on the 9th day. i'm a lil bit anxious about it could you please tell me about window period of pcr?