Now that everyone who wants to sound sophisticated about health care is talking about “personalized medicine”—even the president!—the open question is, what part of medicine is going to get personalized first? Which is to say, what can the intricacies of people’s genomes say about the best way to treat what ails them? The answers may well be in blood. Why is blood a good candidate for genetic personalization? It helps that how genes contribute to blood types is a bit more straightforward than, say, cardiovascular disease. A, B, and Rh (that’s the thing that gives you the positive/negative distinction) are all gene-encoded proteins that stick out like flags on the surface of red blood cells. When the immune system sees a foreign flag, it attacks—in which case the transfusion backfires. Now A, B, and Rh are the most prominent flags, so they are the most important. Behind them are about 35 other key proteins, which Westhoff says the National Center will test for in every single unit of blood they receive.
The trouble with next generation sequencing for personalized medicine is that it’s expensive, and the payoff is uncertain. But you don’t need to get all the way to 300 blood proteins to get more personalized and precise blood typing. Thirty-five is already better than three.