A home test for pre-eclampsia

A saliva test for pre-eclampsia could soon be available OTC. Sanjay Tanday reports

The saliva test designed for home use for mothers-to-be could reduce the risk of pre-eclampsia
The saliva test designed for home use for mothers-to-be could reduce the risk of pre-eclampsia

What is the story?
A simple saliva test could be available in three years that could protect mums-to-be and their babies from pre-eclampsia, media reports suggest.

Up to 1,000 infants and five women die each year in the UK from the condition, according to the charity Action on Pre-eclampsia (APEC).

Globally it kills one woman every six minutes.

But UK researchers believe that a simple saliva test could produce more reliable results than the traditional BP and urine tests currently used by GPs for the detection of pre-eclampsia.

The test, which is designed to be used at home, will allow pregnant women to check for themselves whether they are at risk of the condition.

It will cost less than £100 for a test kit and will be available on the NHS if NICE decides that it is cost-effective.

The first large-scale trial of the saliva test, involving 1,000 women, is to take place in Chichester, West Sussex with results expected early next year, the papers say.

What is the research?
The reports are based on UK research published in the magazine Chemistry & Industry.

Previously, two small-scale trials had been conducted by the researchers, which showed that the saliva test was successful in detecting pre-eclampsia.

The test works by monitoring raised levels of urate, a salt of uric acid, which increases during pre-eclampsia as a result of impaired kidney excretion.

Uric acid levels are also an indication of the general health of a pregnancy. The large-scale Chichester trial will take place at St Richards Hospital.

A total of 1,000 women will be recruited for the trials. The women will each give a saliva sample by placing a cotton swab under the tongue for about a minute.

Each swab will then be squeezed to release the saliva on to a test strip. The saliva test strips will then be sent away for analysis.

The overall goal is to develop a simple traffic light detection kit for use in the home. This will allow women to measure their own saliva sample for the presence of urate without having to visit a GP.

What do researchers say?
Dr Brian Owen-Smith, a retired rheumatologist and inventor of the test, said: ‘A salivary test is simple, non-invasive, quick and cheap and can be done at any time.

‘As a metabolic test independent of BP, it may obviate the need for hospital admission.’

Saliva urate levels are less susceptible to rapid fluctuations than blood urate, making saliva tests more reliable as a diagnostic tool, he said.

‘Saliva is predominantly intracellular water, so salivary urate also reflects total body urate of the mother and baby.

‘Severe pre-eclampsia may occur in the space of a few days between antenatal visits and in situations which make it difficult to diagnoses. This test will allow pregnant women to assess their own salivary urate levels.’

The saliva test is expected to undergo further development and needs to be in line with MHRA regulations before being commercially available, said Dr Owen-Smith.

But despite the interest in the saliva test being shown in the academic and hospital environment, the project remains significantly under-funded and this will affect it when the test is likely to become available for women to purchase in the shops, he added.

What do other experts say?
Michael Rich, chief executive of APEC said: ‘Standard BP and urine tests are unreliable, and there is a lot of scope for user error.’

In addition, high BP can be caused by a variety of factors other than pre-eclampsia, and even when a woman develops pre-eclampsia, problems with high BP may not occur until the later stages, he said.

Newcastle GP Dr Kevan Thorley, who has an interest in pre-eclampsia, said that there was a need for a test to detect pre-eclampsia because there was no such test currently available.

‘Detecting pre-eclampsia by measuring BP and protein urea is not precise as increases in both BP and protein urea can be caused by other factors,’ he said.

‘There have been a number of false dawns when it comes to developing pre-eclampsia tests, but the development of an accurate test would be of enormous value.’

Pre-eclampsia is still one of the unsolved problems in pregnancy, added Dr Thorley.  

Informing patients

  • A saliva test has been shown to detect pre-eclampsia in small-scale studies.
  • The test works by detecting raised levels of urate in saliva samples.
  • Results from the first large-scale trial are expected early next year.

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