This exactly. I knew I was slipping into functional alcoholism, that I was slipping and things were getting out of hand. I happen to visit a doctor for gastroenteritis and answered honestly when asked how much I was drinking. The doctor was concerned and ran a liver function test. Guess what? My liver function was perfectly normal, as was the rest of my bloodwork. I knew I was sick. I felt sick, I looked sick, hell I smelled sick. For me the test was a wake up call: your liver might be fine now, but how would it have felt to be told that at 25, your liver function is declining? It helped me get my act together. Unfortunately fats will latch onto any excuse to avoid changing their unhealthy habits, so their "clean" bloodwork keeps coming up as justification for their lifestyle. Just because disease isn't evident today, that doesn't mean that you are healthy. If you don't mitigate your risk factors, the disease will become evident soon enough.