Alere PROM Test Notice D'utilisation page 4

EN
• Care must be taken when placing the dipstick in
the sample tube. The upper part of the dipstick
must stay dry.
• Do not use a dipstick that has become wet before
use, because moisture damages the dipstick.
• Do not use a dipstick if you notice a blue coloring in
the result area before testing.
• Do not use the dipstick if its aluminum foil pouch or
the seals of the pouch are not intact.
• Use only the swab provided with the kit.
• Improper sampling may lead to false negative
result.
• When dipping, be careful to hold the dipstick in
position (with the dip area in the sample extract)
until the sample liquid front reaches the result
area.
• If the control line does not appear, the test is
invalid, and should be repeated using another
dipstick.
• If the test result cannot be interpreted clearly it is
recommended that the test be repeated.
• At five minutes the appearance of any faint-to-dark
blue test line along with a control line indicates a
positive result. However, do not pay attention to any
lines appearing after 5 minutes.
• If only the control line is visible, the result should
be interpreted as negative only after 5 minutes
have elapsed.
• A positive Alere Actim PROM test result, although
detecting the presence of amniotic fluid in the
sample, does not locate the site of the rupture.
• As with all diagnostic tests, results must be
interpreted in the light of other clinical findings.
All biological specimens and materials must be
treated as potentially hazardous, and disposed of in
accordance with local authority guidelines.
PRINCIPLE OF THE TEST
The concentration of IGFBP-1 (insulin-like growth
factor binding protein-1) in amniotic fluid is 100 to
1000 times higher than in maternal serum. IGFBP-1
is not usually present in the vagina, but after
rupture of fetal membranes, amniotic fluid with a
high concentration of IGFBP-1 mixes with vaginal
secretions. In the Alere Actim PROM test, a specimen
of vaginal secretion is taken with a sterile polyester
swab and the specimen is extracted into Specimen
Extraction Solution. The presence of IGFBP-1 in the
solution is detected using a dipstick.
The test is based on immunochromatography.
It involves two monoclonal antibodies to human
IGFBP-1. One is bound to blue latex particles (the
detecting label). The other is immobilized on a carrier
membrane to catch the complex of antigen and latex-
labeled antibody and indicate a positive result. When
the dip area of the dipstick is placed in an extracted
sample, the dipstick absorbs liquid, which starts to
flow up the dipstick. If the sample contains IGFBP-1 it
binds to the antibody labeled with latex particles. The
particles are carried by the liquid flow and, if IGFBP-1
is bound to them, they bind to the catching antibody.
A blue line (test line) will appear in the result area if
the concentration of IGFBP-1 in the sample exceeds
the detection limit of the test. A second blue line,
the control line, confirms correct performance of
the test.
PERFORMANCE OF THE TEST
The lowest detectable amount of IGFBP-1 in the
extracted sample is 25 μg/l (calibrated against
Behring Institut IGFBP-1 (PP12) preparation Lot
307/323).
Analytical Sensitivity
The analytical sensitivity (detection limit) of the
Alere Actim PROM test was identified by evaluating
different concentrations of IGFBP-1 in extracted
samples on three different lots of the Alere Actim
PROM test. Two different operators each interpreted
ten devices run at each concentration under various
lighting conditions for a total of 60 determinations per
level. The Alere Actim PROM test limit of detection
is approximately 25 µg/l in extracted sample. The
measuring range of the Alere Actim PROM test is
approximately 25-500000 µg/l in extracted sample.
Analytical Specificity
Analytical specificity (cross-reactivity) was tested
with human IGFBP proteins at concentrations ranging
from 10-5000 µg/l of each protein in extracted
sample using three different lots of the Alere Actim
PROM test. No cross-reactivity was seen using
human IGFBP-2, -3, -4, -5 and -6 proteins. The Alere
Actim PROM test is specific to human IGFBP-1.
Repeatability and reproducibility
A panel of specimens consisting of samples of
different IGFBP-1 concentration levels was evaluated
for intra- (repeatability) and inter- (reproducibility)
assay precision. For repeatability the samples
were tested with 10 replicates during the same
day using three different lots of the Alere Actim
PROM test. Repeatable results were obtained. For
reproducibility a study of the Alere Actim PROM test
was conducted at three separate sites. Test operators
(n=9) tested each level on five different days using
one lot of the Alere Actim PROM test. A total of 360
tests were performed (120 per site) with a total of 45
tests per sample type. The overall reproducibility of
the Alere Actim PROM test is 97 % (350/360) with no
significant differences within runs (replicates tested
by one operator), between runs (five different days),
between sites (three sites) or between operators
(nine operators).
Diagnostic performance
The Alere Actim PROM test has been evaluated in
several clinical studies. Selection of typical studies is
shown in FIG 1 on the inner back cover.
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