@Erotic: Given the descriptive nature of the context Best used in relation to testing, incubation and transmission, it is a correct statement. No where in their post do they say testing can stop you from getting something.
What they are saying is: If a person’s test came back positive for, let’s say, the clap, Gonn or even herpes, that person could then take the necessary steps to prevent passing it further along. Knowing their status and hopefully a choice of action being abstinence would help to minimize passing it along to any future play dates. Therefore, that would be a true statement and definitely not a test used as a prophylactic; Since a test is only a medical reading, it bears no physical barrier to protect from anything, it is silly to even call it a prophylactic, let alone compare it to one.
IMHO: Is testing foolproof? No
Does it help to test regularly? Yes, if a test came back positive, it would allow a person to stop from potentially spreading what ever it is FROM THAT POINT FORWARD and take necessary corrective actions.
Then again, some don’t test because they don’t want to know.
~Allen