The United Kingdom's National Institute for Health and Care Excellence (NICE) has updated diagnostic guidance for suspected preterm pre-eclampsia. In the guidance, NICE recommends four placental growth factor (PLGF)-based tests, used with standard clinical assessment.

Pre-eclampsia is a disorder of pregnancy characterized by the onset of high blood pressure and often a significant amount of protein in the urine. When it arises, the condition begins after 20 weeks of pregnancy.

Two of the recommended tests are made by PerkinElmer: Delfia Xpress PLGF 1-2-3; and Delfia Xpress sFlt-1/PLGF 1-2-3 ratio. One of the recommended tests is made by Roche Diagnostics: Elecsys immunoassay sFlt‑1/PLGF ratio. The fourth recommended test is the Triage PLGF test, manufactured by Quidel.

“Pre-eclampsia symptoms are unspecific and could resemble normal pregnancy, however delayed treatment can cause the condition to become potentially life-threatening for the mother and baby,” said Petra Furu, general manager for reproductive health at PerkinElmer. “Rapid diagnosis is essential to identify which pregnancies are pre-eclamptic and may require hospitalization, which is why we are encouraged that NICE has expanded its list of approved solutions for aiding in the diagnosis of this condition.”

According to NICE, PLGF-based testing may particularly benefit groups at higher risk of severe adverse pregnancy outcomes, such as people from African, Caribbean and Asian family backgrounds.

Why NICE made these pre-eclampsia testing recommendations

PerkinElmer's Delfia Xpress PLGF 1‑2‑3 test was not previously recommended by NICE because there was not enough evidence on its accuracy. High-quality evidence now shows that this test, and the DELFIA Xpress sFlt‑1/PLGF 1‑2‑3 ratio assay, have good accuracy for preterm pre-eclampsia, according to the updated guidance.

NICE previously recommended the Elecsys immunoassay sFlt‑1/PLGF ratio and Triage PLGF Test to help rule out pre-eclampsia. But they were not recommended to help diagnose (rule in) pre-eclampsia because of concerns that this could result in people being unnecessarily offered early births. Data now shows that this is not the case, the guidance notes.

Modelling shows that all these tests are cost effective compared with standard assessment when used to help diagnose (rule in) or exclude (rule out) preterm pre‑eclampsia. So these tests are recommended to help plan safe care and a safe birth for people with pre-eclampsia, and also to identify people unlikely to develop pre-eclampsia, and therefore reduce unnecessary hospitalization. The tests may work differently in people who are pregnant with more than one baby. Therefore, NICE has recommended further research to find out how well the tests work in this group. 

There is not enough evidence on whether or not the test should be repeated. Therefore, NICE has recommended testing just once when a person presents with possible symptoms of preterm pre-eclampsia (an episode) and recommended further research on if repeat testing improves outcomes.

The guidance also notes that there is new data for 

There is new data for Brahms sFlt‑1 Kryptor/Brahms PLGF plus Kryptor PE ratio, which was originally not recommended. But the data is lower quality than that for the other tests. Data on test sensitivity and specificity is from two studies, one that was small and one that did not specify the test threshold to use in advance. There is not enough good-quality data to assess how well it works and its cost effectiveness, according to NICE. There is also uncertainty about how the company intends the test to be used. So this test is still not recommended.