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David Grenache, Ph.D.

Salt Lake City, UT

Recent Activity

More on noninvasive prenatal testing for fetal aneuploidy

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

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Laboratory testing for premature rupture of membranes

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

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Should DNA-based tests for Down syndrome screening replace biochemical tests?

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

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DNA-based tests for Down syndrome screening show excellent clinical performance

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

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Screening or diagnostic test. What is the difference?

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

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Screening for neural tube defects

A neural tube defect (NTD) is a birth defect of the spinal cord and/or brain. The term is used to describe a group of disorders that occur very early in pregnancy and can be mild to severe or even fatal. During the first 3 weeks of pregnancy, specific cells fuse... Continue reading

Posted Nov 1, 2012 at The Pregnancy Lab

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The gestational diabetes mellitus debate continues

I have just returned from the annual meeting of the AACC where I attended a very interesting debate on the diagnosis of gestational diabetes mellitus (GDM). I've written about the current controversy in diagnosing GDM before and you can read about those here and here. Basically, the controversy boils down... Continue reading

Posted Jul 22, 2012 at The Pregnancy Lab

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Diligence recommended during lamellar body count validation

Today's post is by a guest author, Patrick Kyle, Ph.D. Dr. Kyle is the Director of Analytical Toxicology and an Associate Director of Clinical Chemistry at the University of Mississippi Medical Center in Jackson, MS. He discovered a curious phenomenon when the lamellar body count is performed on a specific... Continue reading

Posted May 23, 2012 at The Pregnancy Lab

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Should there be a critical value for hCG test results?

A short while back, a colleague asked Ann and me if we were aware of any need to have a critical value for hCG tests. Our colleague had been asked by a physician to implement one in his laboratory because the physician had “missed” a molar pregnancy diagnosis due to... Continue reading

Posted Apr 23, 2012 at The Pregnancy Lab

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Is the qualitative serum pregnancy test obsolete?

I’ve written several times about qualitative hCG tests in this blog. As a reminder, qualitative tests can be performed using urine or serum samples. Urine tests can be performed close to the patient or even at home because the urine sample requires no special processing. However, when serum is the... Continue reading

Posted Mar 27, 2012 at The Pregnancy Lab

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Is it time to abandon the hCG discriminatory zone?

I've written about ectopic pregnancy a few times now (see this and this). The use of hCG testing in the evaluation of a woman with a suspected ectopic pregnancy is invaluable. For many years doctors have relied upon the concept of a "discriminatory zone." That is, an hCG concentration above... Continue reading

Posted Feb 21, 2012 at The Pregnancy Lab

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Molecular testing for Down syndrome: proceed with caution

Ann recently posted about massively parallel genomic sequencing using maternal blood as a screening test for Down syndrome. In it, she described a recently published, multi-center clinical study that validated this molecular test in just over 1,600 women. The test detected 98.6% of the Down syndrome fetuses and had a... Continue reading

Posted Jan 29, 2012 at The Pregnancy Lab

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Screening for Down syndrome: Beginning of a New Era?

David has written previously about the different types of screening tests for Down syndrome (trisomy 21). Although these tests have certainly gotten better over time, even the best among them is subject to less than perfect sensitivity (90%) and a false positive rate of between 2 and 5%. Given the... Continue reading

Posted Jan 20, 2012 at The Pregnancy Lab

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Screening tests for group B strep infection

The most common cause of life-threatening infections in newborns comes from a bacteria known as Streptococcus agalactiae (more commonly referred to as group B streptococcus or GBS). This was stressed in a recent meta-analysis that reported that GBS infection remains an important, global cause of infant mortality. The overall infection... Continue reading

Posted Jan 6, 2012 at The Pregnancy Lab

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Are there any good markers to predict preeclampsia?

David has written about preeclampsia in the past, but I thought I'd talk about some specific studies that have been published on that topic. Recall that preeclampsia is when a pregnant woman develops high blood pressure and protein in the urine after the 20th week of pregnancy and it is... Continue reading

Posted Dec 15, 2011 at The Pregnancy Lab

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Hyperthyroidism and its association with severe vomiting during pregnancy

Hyperemesis gravidarum (HG) is severe vomiting during pregnancy and it occurs in approximately 0.2% of all pregnancies. Interestingly, many patients with HG may display clinical and biochemical symptoms of hyperthyroidism. The name "transient hyperthyroidism of hyperemesis gravidarum" (THHG), has been adopted to describe the syndrome of transient hyperthyroidism in pregnancy... Continue reading

Posted Dec 7, 2011 at The Pregnancy Lab

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CLSI publishes guideline on the assessment of fetal lung maturity by the lamellar body count

I’ve blogged about fetal lung maturity (FLM) tests before but this is exciting news! The Clinical and Laboratory Standards Institute (CLSI) has just published a document that provides guidance to labs that wish to perform the lamellar body count as a test for fetal lung maturity. Disclaimer: I participated in... Continue reading

Posted Dec 1, 2011 at The Pregnancy Lab

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Should all pregnant women be screened for hypothyroidism?

Hypothyroidism affects about 2% of all women but occurs in only about 0.5% of pregnant women. The discrepancy is probably due to the known association between hypothyroidism and infertility. Other causes of inadequate thyroid function during and after pregnancy include iodine deficiency, Hashimoto’s disease, thyroidectomy, radioactive iodine treatment, and subacute.... Continue reading

Posted Nov 18, 2011 at The Pregnancy Lab

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Ectopic pregnancy and the hCG discriminatory zone

I’ve written about the use of hCG testing in the evaluation of patients with suspected ectopic pregnancies. As a reminder, the diagnostic tests used in the work-up of a woman with symptoms of an ectopic pregnancy include a combination of transvaginal ultrasound and the laboratory measurement of serum hCG concentrations.... Continue reading

Posted Nov 7, 2011 at The Pregnancy Lab

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The hCG Diet: Don't waste your money

It's almost predictable. Each time I give a talk about the biochemistry of hCG and clinical uses of hCG tests, I get asked a question about the hCG diet. A comment on a recent post on this blog also asked about its safety and effectiveness. I decided that even though... Continue reading

Posted Oct 30, 2011 at The Pregnancy Lab

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Four reasons for a positive hCG test in the absence of pregnancy

“Why is the pregnancy test positive if she’s not pregnant?” This is a question I’ve been asked several times and it’s a good one. The query usually comes from a nurse, doctor, or other healthcare provider after performing a test for human chorionic gonadotropin (hCG) and getting a positive or... Continue reading

Posted Oct 17, 2011 at The Pregnancy Lab

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Wanted: a rapid pregnancy test using whole blood

Most laboratorians would agree that when it comes to hCG testing for pregnancy status, a blood sample is preferred over a urine sample. Why is that? Following implantation of a fertilized egg, hCG is first detected in the blood. hCG in the urine usually appears a day or two later.... Continue reading

Posted Sep 29, 2011 at The Pregnancy Lab

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Surprising details about the most sensitive urine pregnancy tests

Here’s a multiple-choice question to consider: Which type of qualitative urine hCG test devices (a.k.a pregnancy tests) are capable of detecting the lowest concentrations of hCG? A. The devices that can be purchased at a local pharmacy for use at home (over-the-counter (OTC) tests). B. The devices used in hospitals,... Continue reading

Posted Sep 22, 2011 at The Pregnancy Lab

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Diabetes, fetal lung maturity, and the lamellar body count

I've written a few posts on diabetes during pregnancy lately so thought I'd stick with it a bit longer. This time, however, the focus is on the effect that maternal diabetes has on fetal lung maturity. It's generally believed that fetal lung maturity is delayed in women who have diabetes... Continue reading

Posted Sep 11, 2011 at The Pregnancy Lab

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hCG and the thyroid gland

First things first. The main job of human chorionic gonadotropin (hCG) hormone is to increase the synthesis of progesterone in early pregnancy. Without steadily increasing concentrations of progesterone, an early pregnancy will fail. hCG usually has nothing to do with the thyroid gland. As a reminder, the thyroid gland, located... Continue reading

Posted Sep 1, 2011 at The Pregnancy Lab

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