International Journal of Clinical Medicine, 2011, 2, 307-309
doi:10.4236/ijcm.2011.23052 Published Online July 2011 (
Copyright © 2011 SciRes. IJCM
The AL-SENSE Test Is Reliable for Detection of
Second Trimester Amniotic Fluid
Marwan Odeh1,2, Ella Ophir1,2, Hadar Kesari-Shoham3, Olga Maximovsky1, Jacob Bornstein1,2
1Department of Obstetrics and Gynecology, Western Galilee Hospital, Nahariya, Israel; 2Rappaport Faculty of Medicine, Technion,
Haifa, Israel; 3Commonsense, Caesarea, Israel.
Received December 13th, 2010; revised April 10th, 2011; accepted May 5th, 2011.
Objective: To validate the reliability and stability of the AL-SENSE panty-liner for detection of amniotic fluid in the
second trimester. Study design: Amniotic fluid drawn during amniocentesis between 16 to 23 weeks of gestation was
used for the study.100 µl and 400 µl of amniotic fluid, were dripped onto two panty liners, respectively. After 5 minutes
the indicator strip was removed from the AL-SENSE, dried and examined. The color was recorded at time 0 and 5 min-
utes, and then every 10 minutes for the first 30 minutes, then at 1, 2, 6 and 12 hours. Results: 50 women were enrolled
and 49 completed the study. 100% of both volume samples changed color from yellow to blue during the first 5 minutes
and remained stable after twelve hours of follow-up. In the 100 μl subgroup, seven of the 49 samples (14.3%) had a
delayed color change and in the 400 μl subgroup one of 49 (2.04%) had a delay in change of color. Concl usion s: Am-
niotic fluid drawn during amniocentesis at weeks 16 - 23 of gestation have a positive, stable staining effect on the
AL-SENSE panty liner. Hence, AL-SENSE may be reliable for detection of amniotic fluid leakage during the second
Keywords: Panty Liner, Amniocentesis, Second Trimester, Premature Rupture of Membranes
1. Introduction test, microscopic evaluation for ferning and ultrasound
determination of intra-uterine amniotic volume [2]. These
results were confirmed by another study [3] comparing
the panty-liner test to speculum examination for detec-
tion of ruptured membranes; it found 98% sensitivity
and 65% specificity.
Recently, a diagnostic panty-liner kit—“AL-SENSE”®
(Commonsense, Caesarea, Israel) was developed to de-
tect amniotic fluid leak. Its mechanism of action is de-
scribed elsewhere [1]. The panty-liner has several ad-
vantages. Firstly, it is worn by the women for some
hours, so it reflects a relatively lengthy time period and
not a single point in time, which increases its sensitivity
in detecting minor amniotic fluid leakage. In addition, it
contains a unique polymer that is capable of differenti-
ating amniotic fluid from urine.
In previous third trimester clinical studies [1,2], the
AL-SENSE panty-liner test was documented as a sensi-
tive tool for diagnosing premature rupture of the mem-
branes (PROM) and differentiating amniotic fluid leaks
from urinary incontinence. One study showed 100%
negative and 87.1% positive predictive values, with a
sensitivity of 100% and specificity of 75%. Another
study showed 94.7% negative and 87% positive predic-
tive value with a sensitivity of 96% and specificity of
84%. The panty-liner was compared to a series of con-
ventional tests such as speculum examination, nitrazine
Those studies enrolled women mostly at the third tri-
mester. However, since amniotic fluid leakage during
the second trimester has even more serious complica-
tions and poor outcomes than during the third trimester,
the present study was undertaken to establish the
AL-SENSE reliability in the second trimester and to
validate the stability time of the positive color of
AL-SENSE stains even after exposure to very small of
early second trimester amniotic fluid. The amniotic fluid
was drawn at genetic amniocentesis between 18 and 23
weeks of gestation.
2. Materials and Methods
The study was approved by the local Institutional Re-
view Board (Helsinki committee) and written informed
consent was obtained from each patient prior to enroll-
The AL-SENSE Test Is Reliable for Detection of Second Trimester Amniotic Fluid
The AL-SENSE comprises a regular panty-liner and
is worn as any other hygienic panty-liner. Inside the
panty-liner the AL-SENSE contains one strip of (color)
indicator that is sensitive to pH levels. The indicator
strip reacts immediately to any contact with amniotic
fluid or other vaginal discharge of pH 5.2 or greater.
Observing a change in the color of the pH indicator in-
dicates either a leak of amniotic fluid or a urine leak.
The indicators were placed in a drying box and observed
to determine the stability of the stain.
During amniocentesis performed for medical reasons
(primarily age over 35 years), between 18 and 23 weeks
of gestation, 0.5 ml of amniotic fluid, of the 30 ml usu-
ally drawn, were used for this study.
Two volumes of amniotic fluid, 100 µl and 400 µl,
were dripped onto two AL-SENSE panty liners num-
bered 1 and 2, respectively. After five minutes the indi-
cator strip was removed from the AL-SENSE and the
strips were placed in the drying units.
The color status was recorded from both panty-liners
immediately, after 5 and 10 minutes, and then every 10
minutes for the first 30 minutes and within 1, 2, 6 and 12
hours after removing the indicator strip and placing it in
the drying unit.
3. Statistical Analysis
Statistical analyses were performed using SAS® v9.1
(SAS Institute, Cary N.C., USA). Descriptive statistics
are presented in a table. Study results are presented as
counts or percentages together with a 95% exact bino-
mial confidence interval when relevant.
4. Results
Fifty (50) women were enrolled in the study; 49 (98%)
completed it. One patient was excluded due to a protocol
The distribution of gestational age is presented in Ta-
ble 1; most women were in their 18th -19th week of ges-
One hundred percent of samples in both volumes
(95% CI: (92.75% - 100%)) changed color from yellow
to blue within five minutes and the color remained stable
Table 1. Distribution of gestational age by weeks.
Gestational Week N %
16 1 2.0
17 3 6.1
18 16 32.7
19 21 42.9
20 5 10.2
21 1 2.0
22 1 2.0
23 1 2.0
Total 49 100.0
throughout the twelve hour follow-up period. Initial in-
dicator color change did not occur at time 0 for all the
samples. In the 100 μl subgroup 7 of the 49 samples, or
14.3% (95% CI: (5.94% - 27.24%)), had a delayed color
change and in the 400 μl subgroup 1 of 49, i.e. 2.04%
(95% CI: (0.05% - 10.85%)), showed a delay in color
5. Discussion
In the present study the AL-Sense panty-liner was found
to be very sensitive and changed its color in response to
a very small amount of second trimester amniotic fluid
obtained at amniocentesis. The color change was stable
for 12 hours, the time determined in advance as the
completion of the study. So far, the validity of the
AL-Sense panty liner has been proven in clinical studies
in diagnosing premature rupture of membranes in the
third trimester [1-3]. However, the effectiveness of this
test had not been tested in second trimester pregnancies.
This study utilized amniotic fluid obtained during
amniocentesis. Therefore, the effectiveness of this test
should be verified in a clinical setting, as the color of the
panty-liner may change in reaction to vaginal secretions
when infections that cause elevated pH are present (as
stated by the manufacturer). Nevertheless, Mulhair et al.
[3] found that women with positive high vaginal swabs
did not differ significantly and nine women with positive
high vaginal swab had a negative test (no color change).
The high pH level of amniotic fluid (7.42) even at
very early stages of pregnancy [4], the ability of the
panty-liner to detect it, even in very small amounts (100
µl), and the long term stability of the stain makes it a
very useful tool in diagnosing cases with premature
rupture of the membranes in the second trimester. This
period of pregnancy may be associated with significant
management dilemmas due to the high percentage of
fetal, neonatal and maternal complications with PROM
at that time [5-7]. The high sensitivity of this test in
clinical studies (100%) makes it very helpful in reassur-
ing patients that membranes have not ruptured.
A drawback of this test is its low specificity; hence,
when the test is positive the diagnosis should be verified
by other means. However, in this study, as we dripped
amniotic fluid directly on the panty-liner and there was
no contact with vaginal discharge or other fluide, we did
not include a positive/negative control.
Another possible use of this test is in patients experi-
encing post-amniocentesis fluid leakage. Since most of
these cases may be followed expectantly [8,9] the test
can be used to indicate cessation of amniotic fluid leak-
age (when a positive test become negative).
In conclusion, the panty-liner is effective in the sec-
ond trimester of pregnancy and can be used at that time
Copyright © 2011 SciRes. IJCM
The AL-SENSE Test Is Reliable for Detection of Second Trimester Amniotic Fluid
Copyright © 2011 SciRes. IJCM
to detect small amounts of amniotic fluid leakage, and to
exclude its presence if the leakage consists of urine. It is
very sensitive and detects small amounts of amniotic
fluid drawn during amniocentesis.
As the present study has been conducted in vitro, the
efficacy of AL-Sense should be further verified in clini-
cal studies of women with fluid leakage during the sec-
ond trimester, in the same way as it has been tested in
women during the third trimester.
6. Conflict of Interests
Hadar Kesari-Shoham is employed by the manufacturer
of the AL-SENSE panty-liner.
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