The ability to provide quick information about an individual's health condition, which can help them make better decisions in their life! I do not like that it takes too long for me to get results back after requesting one; this makes waiting uncomfortable at times as well.
It would be nice if you could request multiple tests all together so they are able to give more accurate diagnoses than just looking through your medical history or asking questions of physicians/nurses. This allows patients time to think over what has been said before making any final decision regarding treatment options etc..