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David Grenache, Ph.D.
Albuquerque, New Mexico
Recent Activity
Laboratory tests are not perfect. I hope this does not come to a surprise to anyone. In a perfect world, a lab test would always identify individuals with a specific condition from those who don’t have that condition. Unfortunately, we don’t live in that world and so lab test results... Continue reading
Posted Aug 15, 2018 at The Pregnancy Lab
It has been several years since cell-free DNA (cfDNA) tests for the detection of fetal aneuploidies became available. The first clinical studies of these tests were reported in women who, because of age or other reasons, were already at increased risk of having an affected pregnancy (i.e. "high risk" women).... Continue reading
Posted Apr 17, 2017 at The Pregnancy Lab
"A question some women face: when to freeze their eggs." This was the start of a news piece I heard on NPR as I drove to work this morning. It caught my attention and I realized we haven't spent much time on this blog exploring the tests used to help... Continue reading
Posted Oct 5, 2015 at The Pregnancy Lab
Personalized medicine can be defined as customized disease prevention therapies and drug treatment protocols based on knowledge of an individual’s unique genetic makeup, metabolic profile and clinical presentation. So far, personalized medicine has focused on the prevention and treatment of conditions affecting adults such as cancer and cardiovascular disease. However... Continue reading
Posted Jul 28, 2015 at The Pregnancy Lab
This post was written by Robert D. Nerenz, PhD, an assistant professor of pathology and laboratory medicine at the University of Kentucky, in Lexington. In the United States, an estimated one in seven couples experience infertility and for many of these couples, in vitro fertilization (IVF) represents their best chance... Continue reading
Posted Jul 21, 2015 at The Pregnancy Lab
The American Congress of Obstetricians and Gynecologists (ACOG) have updated their guidance on cell-free DNA (cfDNA) screening tests for fetal aneuploidy. In it, they state that any patient (i.e. women at high-risk OR low-risk for having an affected pregnancy) may choose cfDNA testing but they caution that conventional screening tests... Continue reading
Posted Jul 6, 2015 at The Pregnancy Lab
Testing urine samples for the presence or absence of hCG is commonly performed in hospitals and clinics for the rapid assessment of a woman's pregnancy status. This topic has been discussed several times in this blog (see here and here). Urine hCG tests are hugely popular because they can be... Continue reading
Posted May 18, 2015 at The Pregnancy Lab
The use of cell-free DNA (cfDNA) testing to screen for fetal aneuploidies has been the topic of several posts on this blog. Large clinical studies that have evaluated the performance of cfDNA tests have all arrived at the same conclusion: cfDNA testing is superior to traditional biochemical screening tests for... Continue reading
Posted Apr 27, 2015 at The Pregnancy Lab
This post was written by Robert D. Nerenz, PhD, an assistant professor at the University of Kentucky, in Lexington. In previous posts, we have discussed false negative pregnancy test results caused by hCG beta core fragment (hCGβcf), the predominant form of hCG found in urine after six weeks of pregnancy.... Continue reading
Posted Jan 9, 2015 at The Pregnancy Lab
Timing is everything. A week after I wrote about false-positive NIPT results, the Boston Globe published an article titled "Oversold prenatal tests spur some to choose abortions" written by Beth Daley of the New England Center for Investigative Reporting. The article describes non-invasive prenatal testing (NIPT) using relatively new cell... Continue reading
Posted Dec 29, 2014 at The Pregnancy Lab
© Stuart Miles - NIPT (non-invasive prenatal testing) continues to get lots of attention lately. Indeed, we've written about it extensively on this blog. None of this is suprising because NIPT is a new technology that is continually evolving. Two years ago, I wrote about NIPT here and provided... Continue reading
Posted Dec 8, 2014 at The Pregnancy Lab
Ectopic pregnancy is a potentially life threatening complication of pregnancy. It occurs when the embryo implants outside the uterine cavity, most commonly in the fallopian tube. Common symptoms include nausea, abdominal pain, and slight vaginal bleeding. Approximately 2% of all pregnancies are ectopic pregnancies and they require emergency treatment to... Continue reading
Posted Jul 23, 2014 at The Pregnancy Lab
Just over 3 years ago, I blogged about the declining use of fetal lung maturity (FLM) tests and questioned their clinical usefulness. I wanted to revisit this same issue again because a recent report has validated my sentiments. Actually, there have been two recent reports on this topic but the... Continue reading
Posted Jun 10, 2014 at The Pregnancy Lab
This year marks the 30th anniversary of the use of laboratory tests to screen pregnancies for Down syndrome. The tests have evolved over the last three decades and as have their ability to detect affected fetuses. Currently there are several different lab tests available to screen for Down syndrome during... Continue reading
Posted May 3, 2014 at The Pregnancy Lab
This blog has covered the topic of gestational diabetes mellitus several times. Recent big news in this arena is the recommendation from the U.S. Preventative Services Task Force (USPSTF) that all pregnant women be screened for gestational diabetes mellitus (GDM) after 24 weeks of gestation. The USPSTF is an "independent... Continue reading
Posted Jan 29, 2014 at The Pregnancy Lab
The rapid assessment of pregnancy status is important in urgent health care settings. Determining if a woman is pregnant or not is necessary to: Determine if symptoms such as abdominal pain, vaginal bleeding, and/or vomiting are due to pregnancy; Prevent fetal exposure to sources of radiation (x-ray, CT, scan, etc);... Continue reading
Posted Oct 24, 2013 at The Pregnancy Lab
Today's post is by a guest author, Ian Schwartz, M.D. Dr. Schwartz is an assistant professor of emergency medicine at the Yale University School of Medicine and the former medical director of the adult emergency department at the Yale-New Haven Hospital in New Haven, CT. Here, he provides his perspective... Continue reading
Posted Oct 2, 2013 at The Pregnancy Lab
A recent post on this blog described the inability of qualitative point-of-care (POC) hCG tests to detect hCG when it was present in urine or serum at a concentration that should, according to the test manufacturer, always be detected. The inability of these devices to detect hCG is a serious... Continue reading
Posted Sep 10, 2013 at The Pregnancy Lab
Today's post is by a guest author, Dina N. Greene, Ph.D. Dr. Greene is a Scientific Director at Northern California Kaiser Permanente Regional Laboratories in Berkeley, CA. She discovered that qualitative hCG tests may not be as analytically sensitive as we all have come to believe and she shares her... Continue reading
Posted Aug 29, 2013 at The Pregnancy Lab
I'm beginning to wonder what could possibly come next. Last month, Swiss Precision Diagnostics (via its Procter & Gamble partner) unveiled its newest product in consumer diagnostics: the Clearblue Advanced Pregnancy Test with Weeks Estimator. This urine hCG test determines pregnancy status but also provides an estimate of the number... Continue reading
Posted Jun 9, 2013 at The Pregnancy Lab
We have written about nonivasive prenatal testing (NIPT) on this blog several times. Because they are so new, the landscape around these tests is continually evolving. The American College of Obstetricians and Gynecologists (ACOG) published guidelines on these tests in December of last year. Just this week, the American College... Continue reading
Posted Apr 8, 2013 at The Pregnancy Lab
This post is by a guest author, Douglas Stickle, Ph.D. Dr. Stickle is a professor in the Department of Pathology at Thomas Jefferson University and the director of chemistry and point-of-care testing at Jefferson University Hospitals in Philadelphia, PA. Rupture of membranes (ROM) is the term used to describe the... Continue reading
Posted Mar 5, 2013 at The Pregnancy Lab
In a previous post I described the clinical performance of DNA-based screening tests for fetal aneuploidies like Down syndrome. Overall, these tests have excellent detection rates (~99%) with very low false-positive rates (~0.2%). In other words, these tests are about 99.0% sensitive and 99.8% specific. With performance like that one... Continue reading
Posted Jan 6, 2013 at The Pregnancy Lab
The use of biochemical screening tests to identify pregnant women who are at high risk of having a fetus with Down syndrome is well established. Biochemical screening began nearly 30 years ago and, over the years, the tests have evolved and improved. Now there’s a new kid on the screening... Continue reading
Posted Dec 11, 2012 at The Pregnancy Lab
Today was an interesting day at work. A genetic counselor I work with emailed me that a pregnant patient wanted to have "every single Down syndrome screening test that was available." While this was problematic in and of itself (more about that later), this patient also planned to have an... Continue reading
Posted Nov 26, 2012 at The Pregnancy Lab