There is always news being made in the realm of prenatal testing, the subject of this month's Continuing Education cover story. Laboratorians need to keep up to date on all the tests they run, of course—but no area of testing may have both the scientific and emotional dimension that this one has. Laboratorians are part of the team that brings babies into the world—healthy and ready to begin the journey of life.
In his cover story article (pages 8-11 in print, online: MLO Feb. Cover Story), Dr. David Grenache focuses on the crucial topic of fetal lung maturity (FLM). He makes the important point that the landscape of FLM testing has changed considerably since the end of 2011, when Abbott Laboratories retired the TDx and TdxFLx instruments that perform the surfactant-to-albumin ratio and ceased manufacturing the reagent. He reviews the remaining FLM testing options for labs, and notes that the lamellar body count (LBC) test may be the most preferred alternative. He refers readers to a document published on the subject by the Clinical and Laboratory Standards Institute (CLSI) last November, Assessment of Fetal Lung Maturity by the Lamellar Body Count. This document, as well as Dr. Grenache's cogent summary of the issues involved in FML testing, are important reading for all laboratorians.The cover story also includes sidebars on recent CLSI guidelines on maternal serum screening and newborn screening for cystic fibrosis.
A second cover story feature, written by Dr. Louise Kenny (pages 12-14 in print, online: MLO Feb. Cover Story Plus), focuses on prenatal testing for the serious disorder pre-eclampsia. She stresses the diagnostic value of measuring placental growth factor (PIGF). Significant differences in PIGF levels are a strong indicator of pre-eclampsia, which heretofore has often been diagnosed based on two less dependable, non-specific markers, hypertension and proteinuria.
During the preparation of the February issue of Medical Laboratory Observer, two news releases related to prenatal testing and newborn screening came across my desk:
A study reports in the current issue of Pediatric and Developmental Pathology that researchers are working to identify the gene responsible for a rare but often fatal heart condition in infants, histiocytoid cardiomyopathy (HC). Comparing cardiac tissue of 12 patients with HC and 12 age-matched controls, researchers found decreased protein expression, or downregulation, in two sets of genes aligned sequentially along the genome. This suggests several genes as candidates for the mutation that may predispose individuals to HC. The downregulation of a particular gene could result in reduced survival of cardiac myocytes, leading to cardiac failure. The candidate genes now will offer a starting point for further research on inherited patterns of mutation, as researchers continue to zero in on the cause of this genetic disorder.
Another study, published in the January edition of The FASEB Journal, describes findings that could lead to a non-invasive test that would let expecting mothers know their baby's sex as early as the first trimester of pregnancy. Such a fetal gender determination test would be the first of its kind, and an attractive alternative to amniocentesis or chorionic villus sampling. Researchers discovered that various ratios of two enzymes (DYS14/GAPDH), which can be extracted from a pregnant mother's blood, indicate whether the baby will be a boy or a girl. They collected maternal plasma from 203 women during their first trimester. The presence of circulating fetal DNA was confirmed by a quantitative methylation-specific polymerase chain reaction of U-PDE9A. Multiplex real-time PCR was used to simultaneously quantify the amount of DYS14 and GAPDH in maternal plasma. The results were confirmed by phenotype at birth.
Further news about studies such as these, and many more that are sure to follow, may find their way into the pages of future issues of MLO. We will continue to supply information that laboratorians need—information about prenatal and newborn testing, and about the broad panoply of topics that must be part of today's laboratorians' arsenal of knowledge.
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