NICE recommends the Triage PlGF test (Alere) and the Elecsys immunoassay sFlt-1/PlGF ratio (Roche Diagnostics) to help rule-out pre-eclampsia in women between their 20th and 35th week of pregnancy.
The tests detect changes in the blood that can mean the placenta is not developing properly.
NICE only recommends the use of the tests to help rule-out pre-eclampsia. They have not been recommended to help doctors diagnose pre-eclampsia. The guidance calls for further research on the two tests to see if they can be used in future to rule-in pre-eclampsia.
Dr Jenny Myers, specialist diagnostics assessment committee member, said: “At the moment women with suspected pre-eclampsia often have to come into hospital for 24 to 36 hours so we can make a diagnosis, but now, for women between 20th and 35th week of their pregnancy, these new tests may avoid the need for admission to hospital.”
Dr Myers, who is also Senior Lecturer and Consultant Obstetrician, Maternal and Fetal Health Research Centre, Central Manchester Foundation Trust, said: “The tests will be extremely valuable to help rule out pre-eclampsia before the 35th week of pregnancy, when approximately 1/3 of women with pre-eclampsia are diagnosed.
“Doctors will need to be clear with patients, depending on which test is used, the result is only valid for 7 to 14 days and neither test definitively rules out pre-eclampsia for the rest of the pregnancy.
“However these tests represent a great stride forward in the management and treatment of pre-eclampsia.”
It is estimated that pre-eclampsia, and associated eclampsia, are the second leading cause of direct maternal deaths in the UK2. Pre-eclampsia is caused when the placenta doesn’t develop properly because of a reduced blood supply. Signs of pre-eclampsia include high blood pressure (hypertension) and the presence of protein in the urine (proteinuria).
If it’s not treated, there is a risk that the mother can develop potentially life-threatening eclampsia.
Pre-eclampsia can lead to liver, kidney and lung failure, problems with blood clotting and stroke later in life. It is also thought that women who develop pre-eclampsia during pregnancy may have a greater risk of cardiovascular disease later in life. Hypertension and pre-eclampsia can cause growth problems in the baby, premature birth, or stillbirth.
The only cure for pre-eclampsia is to deliver the baby.
The recommended tests measure levels of placental growth factor (PlGF) in the blood. PlGF is a protein that helps the development of new blood vessels in the placenta. In pre-eclampsia levels of PlGF can be abnormally low and could be an indicator that the placenta is not developing properly.
The Elecsys immunoassay sFlt-1/PlGF ratio also measures a protein called soluble FMS-like tyrosine kinase-1 (sFlt-1). The protein sFlt-1 stops other proteins that help to form blood vessels, like PlGF, from working. In pre-eclampsia if sFlt-1levels are higher than those seen in normal pregnancy it could be an indicator the placenta is not developing properly.
Professor Carole Longson, director of Centre for Health Technology at NICE, said: “Until now there have been no tests which doctors can use to confidently rule-out pre-eclampsia. This has meant women with suspected pre-eclampsia often need increased monitoring or have to stay in hospital. Apart from being inconvenient, this can increase anxiety at what might already be a stressful time.
“In recommending these tests the committee highlighted the importance of making sure laboratories explain to clinicians if a test result doesn’t rule-out pre-eclampsia they should not automatically diagnose women with pre-eclampsia.
Instead doctors should follow existing NICE guidelines to make such a diagnosis. This is so that babies aren’t delivered unnecessarily early as a result of these tests. ”
The guidance recommends further research is carried out on using these tests in women with suspected pre-eclampsia to help diagnose pre-eclampsia.
Two further tests were considered as part of this assessment. The guidance does not recommend the DELFIA Xpress PlGF 1-2-3 test (Perkin Elmer) and BRAHMS sFlt-1 Kryptor / BRAHMS PlGF plus Kryptor PE ratio (Thermo Fisher Scientific) for routine adoption in the NHS. Further evidence to show the clinical effectiveness of these tests including diagnostic accuracy and analytical validity is needed.
- NHS Choices (accessed March 2016) http://www.nhs.uk/conditions/pre-eclampsia/pages/introduction.aspx
Notes to Editors
- The diagnostics guidance on tests to aid the assessment of suspected pre-eclampsia is available on the NICE website at https://www.nice.org.uk/guidance/dg23.
- In normal pregnancy, PlGF levels rise and peak at 26 to 30 weeks, so when PlGF levels do not rise during pregnancy this may be an indicator that the placenta is not developing properly.
- NICE guideline on antenatal care (2008; CG62) recommends measuring blood pressure and testing urine for proteinuria to screen for pre-eclampsia at each routine antennal visit.
- The NICE pathway on pre-eclampsia describes the assessment and treatment of women at risk of pre-eclampsia or with pre-eclampsia. The NICE guideline on hypertension in pregnancy was used to create the pathway (2010; CG107).
About the NICE Diagnostics Assessment Programme
- For further information about the NICE diagnostics assessment programme see Developing NICE diagnostic technologies guidance
- Topics to be considered by the Programme are routed through the related Medical Technologies Evaluation Programme. Further information about this can be found at Developing NICE medical technologies guidance
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