Despite the rapid advancement of medical technology it is not that common for a new test or medicine or vaccine to really get us (doctors) all riled up. This week I watched (and participated) in feathers getting ruffled by a new test that will be available in our community next week. After hearing a talk about it earlier in the day I tried to explain it to my husband, and despite his own large medical knowledge base he was like, “oh, that’s interesting” and I was like IT IS NOT INTERESTING IT IS FREAKING AMAZING AND SCARY AT THE SAME TIME!
So now you’re wondering what this new test might be? It is called cell free fetal DNA testing. It is a test done on a small blood sample from a pregnant woman that is able to differentiate fetal cells from maternal cells and then run DNA testing on those fetal cells. The results are amazingly accurate (around 98%) even done at a very early gestational age (7 weeks) although it sounds like the commercial tests available recommend testing around 10 weeks, probably to increase accuracy.
Here are the really cool medical things this test will be able to do: 1. Determine trisomy disorders (like Down’s syndrome) at a very early gestational age without any invasive testing (like chorionic villus sampling or amniocentesis) with amazing accuracy. 2. Determine a male or female fetus in cases where there may be a sex-linked inherited disorder. 3. Determine the fetus’s blood type so that we can make decisions about whether or not to give rhogam or how much monitoring is necessary in an already isoimmunized patient. 4. Determine paternity for cases of potentially inherited disorders.
Here is the scary part. This gives us the ability to potentially analyze every fetal gene at a very early gestational age and not in some weird future reality, but very soon. Right now the information is limited, but it is certainly possible that in very short order, after a single blood draw, you could be handed a multi-paged report with information about your baby’s DNA. And you could make decisions about that, like, “hm, I don’t think I want a blue eyed, brown haired boy with a 75% risk of developing X, Y, Z disease, I’ll terminate and try again.” Self-selecting your child based on the genetic make up of the fetus is now a real possibility without much risk.
I’m actually not that worried about the medical community becoming a gateway for misuse of the test; I trust my colleagues and I think most of us feel an ethical obligation to only use medical tests to help make medical decisions. I’m more concerned that private companies will get in on this, and in fact, I think it has already started for both paternity and sex determination. I would imagine the only thing really holding people back right now is the cost (around $1500), although I think there are people out there who would shell out that kind of money to find out the sex of their baby at such an early age and with such accuracy. It will be very interesting to see how all of this plays out!
