Maternit21 vs. Quad Screen
If you’ve been pregnant, you’ve likely heard of the Quad or Triple Screen tests. Based on your beliefs and personal choice, you may have taken this maternal blood draw test. Allow me to tell you why the Quad Screen spells potential mental D-I-S-A-S-T-E-R for people with mild anxiety, or people like me with OCD (more on that another day).
During my first pregnancy in 2010, my doctor offered the quad screen during my second trimester as per obstetric standard. She stated that about half of patients at my clinic tend to take the screen. I’m an information junkie with major anxiety, so I just HAD to get it done. My results fell way within the reference ranges for all the trisomies it tests for (18 and 21), something like 1/several thousand for both. Surprisingly, I didn’t think much more about it for the rest of my pregnancy, and my daughter was born with the typical number of chromosomes. I was so traumatized by the forceps delivery pain, but happy with my healthy daughter.
Fast forward to my second pregnancy in 2012. Of course I took the quad screen, not even a question in my mind. My doctor emailed a few days later with the “normal” results. Naturally, I didn’t think much about it, and lived in relative peace for a few weeks (I say relative because I was working and dealing with a toddler). Finally and inevitably, my lovely OCD brain decided to tell me, “hey Kavin! You should totally look at your detailed results from the quad screen! Do it, do it, do it!” So I logged in to my trusted friend, My Chart. And lo and behold I saw this:
I know, it says the screen is within normal limits. But for Down Syndrome it says “Risk after test 270.” For those not familiar with how the Quad Screen works, it basically measures the levels of four analytes in the maternal bloodstream. Based on the comparative levels of these four, along with data like race, age, weight, gestational age, etc., it comes up with a statistical likelihood that the fetus carries certain genetic disorders. Needless to say, a statistical likelihood isn’t a yes or no answer, and some of us are real yes or no answer people.
Anyway, the cutoff listed by the lab that processed my sample is 1/150 for a flag. But then my obsessive brain said, “hey you! Check the cutoff for other labs. Because seriously, 1/270 seems too high for comfort. You went from a risk of 1/720 before the test to 1/270. That’s a lot, dude.” And oh boy did I find out that Mayo Clinic says the cutoff for a flag is 1/270. This is Mayo, and I trust them. Wow. Not cool. Don’t get me wrong, I’m not at all diminishing the value of individuals with Down Syndrome. I know they can be lovely people with unique personalities and fulfilling lives. This is not a debate on the value of Down Syndrome individuals. However, I am not strong enough to handle the potential health problems and heartache associated with the condition.
I also understand genetics and statistics enough to have known, rationally, what these numbers meant. I heard from various health professionals and family members that you can’t compare one lab’s cutoff to another’s, yadda yadda yadda. But I wanted a more conclusive answer. So, I visited a genetic counselor.
This wonderful woman validated my concerns, although they didn’t necessarily deserve validation. Once she knew I understood the results, she offered me the Maternit21 test. I had heard of the test, but didn’t know it was available to me. For those of you not familiar with Maternit21, it detects the levels of certain chromosomes in the maternal bloodstream to test for common chromosomal abnormalities, as well as presence of absence of Y chromosome. Feel free to read more about it, but basically this is as close to a yes or no answer you can get without invasive testing. Miss Incredible Genetic Counselor said insurance wouldn’t cover it, but that Sequenom was only charging patients a max of 300-ish dollars. Let me tell you, I handed over my credit card and had my blood drawn before I left the clinic. I told myself that if the results came back negative, I would not allow myself any more mental strife on this subject.
A little over a week later, I got the call that my results were normal. Normal! And on top of that, the test had detected presence of Y chromosome in my bloodstream. Meaning unless I unknowingly carried some really uncommon permutation of sex chromosomes, my baby was definitely a boy. (We already suspected this, as we’d had the 20 week ultrasound by then, and were told, “that is definitely not a leg.”)
Fast forward a few months, and my baby boy was born with a typical number of chromosomes. The epidural didn’t work so well again. Still, I was thrilled to email the genetic counselor to confirm the Maternit21 results were accurate, and to thank her profusely again. Disclaimer: I don’t work for Sequenom, but I would highly recommend this to anyone with mild to moderate anxiety, OCD, or just pregnancy cray. It’s worth the peace of mind, especially if you already have a toddler.
Note- Here is a related piece from the author: Richard Dawkins’ moral policing aside, new era of fetal diagnostics underway