WASHINGTON – A number of clinical laboratory tests exist for the prediction of premature birth, but there is no consensus in the medical community on how effective these tests are and how they should be used in clinical practice. To bring much-needed clarity to this subject, AACC has issued a new guidance document that advises against the routine use of these tests, citing evidence showing that the tests do not improve outcomes for patients at risk of premature delivery or for their babies.
Read the guidance document here: https://www.aacc.org/science-and-research/aacc-academy-guidance/laboratory-testing-for-the-assessment-of-preterm-delivery
Premature birth is the second most common cause of infant death in the United States, and it also places surviving infants at risk for numerous complications, ranging from respiratory distress syndrome to neurodevelopmental disabilities. Early identification of patients who will deliver preterm is critical in that it enables the timely initiation of therapies that accelerate fetal lung maturation, improve neurological outcomes, or even prolong time to delivery. It also prevents these therapies from being given to patients who aren’t at risk for preterm delivery and who may be harmed by these treatments as a result. However, identifying patients at risk of premature delivery is challenging, particularly because the symptoms associated with the onset of premature labor are common even in pregnant patients who aren’t at risk for delivering early. To try to improve this situation, the medical community has turned to clinical laboratory tests that could potentially predict which patients will deliver preterm. These tests measure fetal fibronectin (fFN), interleukin 6, and placental alpha macroglobulin-1 (PAMG-1)—but no studies to date have definitively shown that they work.
In light of this, AACC’s guidance document—developed by laboratory medicine experts in the association’s Academy in collaboration with an OB-GYN specializing in prenatal diagnosis—recommends against using any of these tests in the routine evaluation of women with symptoms of preterm delivery. The guidance explains that this is because all three tests have low positive predictive values, which means that many women whom these tests identify as being likely to deliver prematurely will not actually give birth early. The one major exception to this blanket recommendation is that, in patients who present with symptoms of premature labor and who are at high risk of preterm delivery due to cervical length, a positive PAMG-1 result may help to identify those who are likely to deliver within 7 days.
AACC’s guidance document also recognizes that many professional societies in the U.S. and Europe have differing stances regarding the utility of fFN for predicting preterm birth, which might make some OB-GYNs reluctant to discontinue its use. Taking this into consideration, the guidance urges laboratory professionals and OB-GYNs to discuss all available recommendations on preterm birth testing together, and to take a collaborative approach to developing institutional testing strategies for preterm birth that best meet the needs of their local patient populations.
“Currently, available biomarkers for the prediction of [preterm birth] provide limited value when incorporated into diagnostic algorithms most frequently used in the U.S.,” said the guidance’s senior author, Dr. Robert D. Nerenz. “One possible solution is to identify novel diagnostic tools with improved [positive predictive value]. An alternative solution is to limit biomarker testing to high-risk women. Both solutions have the potential to improve outcomes, but will require a more detailed understanding of the mechanisms responsible for initiating labor and delivery or the implementation of screening steps that limit testing to women at high risk of [preterm birth].”
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.