AmniSure ® Performance Data

AmniSure ® is a one-step immunochromatographic assay. Three monoclonal antibodies are used in the test to detect PAMG-1. AmniSure ® works within a wide range of PAMG-1 concentrations in vaginal secretion (from 5 ng/ml to 100 mcg/ml). Diagnostic accuracy of the test does not depend on the term of pregnancy and practically does not depend on the volume of released amniotic fluid.

Test Characteristics
  • Sensitivity = Over 99%
  • Specificity = Over 99%
  • Positive Predictive Value = Over 99%
  • Negative Predictive Value = Over 99%

    • If the fetal membrane rupture is detected during pre-term or full-term pregnancy, different variants of patient treatment are available: prophylaxis of intrauterine infection of the fetus, prophylaxis of the respiratory syndrome of the fetus or stimulation of delivery.

    As a first step of the test, the vaginal swab is used non-invasively to take a sample of vaginal secretion. The swab is then dipped into a vial with solvent that extracts the sample substance from the swab. Finally, the test strip (dipstick) is dipped into a vial and result is read within 5 to 10 minutes.

    The Pad Region of the test strip is dipped into the vial (see CHART ). A-MABs in soluble form are located in the Pad Region. These MABs have colloidal gold particles attached to them. When A-antibodies come in contact with PAMG-1 protein resulting from the rupture of fetal membrane and the subsequent leakage of the amniotic fluid, they “catch” PAMG-1 and transport it to the test region.

    The test region of the test strip has B-antibodies immobilized on it. B-antibodies “meet” PAMG-1 bound to A-MABs flowing up from the Pad Region. This “meeting” immobilizes the system of PAMG-1/A-MABs, resulting in a brown/yellow stripe that becomes visible in the test region. This stripe is produced by dye gold attached to A-antibodies and indicates a rupture of fetal membranes.

    The second stripe, the one in the control region, has nothing to do with fetal membrane rupture. It is designed to provide indication that the test strip is functioning well. This stripe appears when rabbit anti-mouse IgG antibody (not shown in the CHART ) catches the mouse A-antibody with dye gold. Dye gold gives the resulting stripe its color.

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