WASHINGTON – A study in AACC’s The Journal of Applied Laboratory Medicine has for the first time established female-specific reference ranges for several biological variables that play key roles in thrombosis—or blood clotting—during pregnancy. This research could help lower the high U.S. maternal death rate by enabling more precise identification of pregnant women at risk for thrombosis-related complications such as preeclampsia.
The U.S. has a higher maternal death rate than any other industrialized country, with an estimated 26.4 mothers dying for every 100,000 live births as of 2015. Many of these deaths are caused by thrombosis-related complications such as preeclampsia, for which women are at higher risk if they have an underlying condition known as thrombophilia. Because of this, if a woman experiences a thrombosis-related complication during pregnancy, it is important that she undergo testing for thrombophilia after delivery (when clotting factors are no longer influenced by pregnancy). This information is integral to guiding care in potential future pregnancies. Diagnosing thrombophilia with accuracy in women is challenging, however, in part because the range of normal values—or reference ranges—for thrombophilia tests are based on male or mixed-sex populations, even though levels of certain clotting and anti-clotting factors differ significantly between women and men.
A team of researchers led by Moniek P.M. de Maat, PhD, of Erasmus University Medical Center Rotterdam in the Netherlands, has now demonstrated that the use of precise female-specific reference ranges significantly refines thrombophilia test results. To calculate female-specific reference ranges, the researchers measured the levels of 10 major clotting and anti-clotting factors in blood collected from 55 healthy women 6 months after an uncomplicated pregnancy. Next, the researchers investigated the impact of female-specific reference ranges on thrombophilia diagnosis. To do this, they collected blood 3 months postpartum from 61 healthy women with an uncomplicated pregnancy and 197 women who experienced preeclampsia. They then measured the 10 clotting and anti-clotting factors in these samples, and interpreted the results using both the female-specific reference ranges and standard reference ranges.
Overall, de Maat’s team found that female-specific reference ranges ruled out a greater number of women as negative for thrombophilia. When using standard reference ranges, 48% of healthy women and 26% of women with preeclampsia tested negative for thrombophilia, but with female-specific reference ranges, 89% of healthy women and 66% of women with preeclampsia tested negative. This shows that female-specific reference ranges could significantly improve maternal care by enabling healthcare providers to better target treatment and allocate resources for women who are truly at risk for recurring thrombosis-related pregnancy complications.
“When using [women-specific reference ranges] as compared with routine reference ranges, we found significantly more normal results with regard to thrombophilia in healthy women and in women diagnosed with [preeclampsia],” said de Maat. “This finding indicates that [women-specific reference ranges] should be used to interpret hemostatic variables in this group as false classification can have major consequences for future pregnancies and other prothrombotic situations throughout life.”
Dedicated to achieving better health through laboratory medicine, AACC brings together more than 50,000 clinical laboratory professionals, physicians, research scientists, and business leaders from around the world focused on clinical chemistry, molecular diagnostics, mass spectrometry, translational medicine, lab management, and other areas of progressing laboratory science. Since 1948, AACC has worked to advance the common interests of the field, providing programs that advance scientific collaboration, knowledge, expertise, and innovation. For more information, visit www.aacc.org.
Launched by AACC in 2016, The Journal of Applied Laboratory Medicine is an international, peer-reviewed publication that showcases the applied research in clinical laboratory science that is driving innovation forward in healthcare.