It was a loneliness Sherlock noted for two reasons. One, it was perfectly reasonable for a lonely teenager to live in a fantasy world of vampires, given the popularity of Twilight and all of the Twilight copycat television programs and films. The second reason was more personal.
"Urine," he replied, dropping a few milliliters of a clear solution into one of the tubes. He gave it a swirl and nearly smiled. "Post-mortem toxicology. And this gentleman's wife is going to be very relieved to know she has a case against a certain drug company."