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Using AmnioSense to Detect
Amniotic Fluid Leakage.
Introduction: The AmnioSense
panty liner is the only non-intrusive monitor for amniotic fluid leakage that can be
used at home. It allows women to monitor for amniotic fluid leakage and
differentiate this from urine leakage. The test has obvious benefits to
both patient and healthcare professional. It also has possible cost benefits
to the NHS because current guidelines require women be admitted if amniotic
fluid leakage is suspected. Many such admissions are unnecessary and can
create anxiety for patients and needless expense for the NHS.
Undetected leakage of amniotic
fluid can also cause serious problems for both mother and baby. The risk
of infection to both of them is is significantly increased if the amniotic
fluid becomes contaminated.
Technology: The AmnioSense
product conveniently monitors for amniotic fluid leakage whilst a woman
goes about her normal daily routine. At the end of the day or as soon
as any wetness is felt the woman simply removes an indicator strip from
the panty liner and checks for a change in colour. If a blue-green colour
is seen then amniotic fluid is present and the woman should immediately
contact her midwife or doctor for further advice. The test is clearly
of value to all women after 36 weeks of pregnancy but it is also of benefit
after amniocentesis and any other high risk patient categories.
The AmnioSense test works by
changing colour upon contact with amniotic fluid which normally has pH
of 6.7 or more. The AmnioSense panty liner membrane is specific to amniotic
fluid leakage and even if contaminated with relatively alkaline urine
in the pH range 5.5-7.5 will not give a false positive results. The reason
for this is that the technology gives a reversible colour reaction with
urine after 10 minutes.
AmnioSense is also better than
existing delivery room tests in the sense that it monitors continually
whereas spot tests can give false negative results by missing intermittent
leakage.
Clinical Study: In a
clinical study involving 104 women, aged 20-40 years, entering hospital
for a routine examination or for delivery. Each woman was given a single
panty liner to use during the waiting period and the results obtained
were compared to the Nitrazine pH test, visual check by a speculum examination
and if negative by an additional ferning test. If subjects were suspected
of having bacterial vaginosis or Trichomonas vaginalis infections a vaginal
swab was obtained and sent for laboratory analysis. Of these 104 women
studied 54 were shown to have amniotic fluid leakage (52 with identified
wetness and 2 without any declared wetness) and 50 were shown to have
no amniotic fluid leakage.
The overall results showed
a sensitivity of 100% ie all 54 cases of confirmed amniotic fluid leakage
were identified correctly, and a specificity of 84% ie 42/50 women had
true negative results. However, the panty liner technology will also detect
cases of vaginal infection, because of the presence of vaginal discharge
with high pH, and it was noted that 4/8 women with false positive AmnioSense
results were diagnosed as having bacterial vaginosis or Trichomonas vaginalis.
The identification of vaginal infection is an important clinical observation
and given that such cases require medical follow-up we conclude that the
AmnioSense product yields an overall sensitivity of 100% and specificity
of 92%.
Conclusions: This clinical
study supports the use of AmnioSense as a monitor of amniotic fluid leakage
which can bring support and comfort to all pregnant women and their healthcare
providers by reliably identifying when amniotic fluid leakage occurs.
The test is particularly beneficial to high risk groups because of its
efficacy and the likelihood of reduced patient anxiety. The test has the
additional advantage of detecting some cases of vaginal infection that
will benefit from medical follow-up.
The test is a Class 1 Medical
Device and is sold CE marked and compliant with the EU Medical Device
Directive.
Robert D. Barlow PhD, C.Chem,
MRSC, December 2003
Copyright
Med-Direct International Ltd 2003
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