INTENDED USE

The iGFBP-1 Rapid Test Kit is a visually interpreted, qualitative immunoassay rapid test for the detection of amniotic fluid in cervicovaginal secretions during pregnancy. The iGFBP-1 Rapid Test Kit detects IGFBP-1, a major protein in amniotic fluid and a marker of the presence of amniotic fluid in a vaginal sample. The test is intended for prescription use in the point of care and clinical laboratory settings to help diagnose the rupture of fetal membranes (ROM) in pregnant women ≥ 29 weeks gestation who present with signs, symptoms or complaints suggestive of ROM.

SUMMARY

Premature rupture of fetal membranes (PROM) is associated with increased risk of intra-uterine infection and thus increases the risk of both maternal and perinatal morbidity and mortality. This makes well-timed and accurate diagnosis of the condition important.
When PROM occurs at term (≥ 37 weeks gestational age), labor typically ensues spontaneously or is induced within 12 to 24 hours. If membrane rupture occurs before 37 weeks, it is referred to as preterm PROM.1 Literature supports that PROM affects 3% to 4.5% of all pregnancies and that less than (<) 1% of pregnancies are complicated by PROM before viability.
Management hinges on knowledge of gestational age and evaluation of the relative risks of preterm birth that could occur with expectant management. The iGFBP-1 Rapid Test Kit is intended to assist the treating clinician in making an informed decision about how to manage the patient.
The concentration of IGFBP-1 (insulin-like growth factor binding protein-1) in amniotic fluid is 100–1,000 times higher than that in maternal serum. IGFBP-1 is not usually present in the vagina or cervix, but after rupture of fetal membranes, amniotic fluid with a high concentration of IGFBP-1 mixes with vaginal fluids. In the iGFBP-1 Rapid Test Kit, a specimen of vaginal fluid is taken with a sterile polyester swab and the specimen is extracted into the Specimen Extraction Solution. The presence of IGFBP-1 in the extracted sample is detected using a test kit.
The main challenge in diagnosing PROM is to distinguish small amounts of amniotic fluid from other body fluids which may be present in the vagina or cervix. The detection limit of the iGFBP-1 Rapid Test Kit (25 μg/L IGFBP-1 in the extracted sample, corresponding to 400 μg/L IGFBP-1 in the original sample) is above the highest known IGFBP-1 level (300 μg/L IGFBP-1) in maternal blood. The test is also sensitive enough to detect less than one micro liter of amniotic fluid.

PRINCIPLES

The test is based on immunochromatography. It utilizes two mice monoclonal antibodies to human IGFBP-1. One of the two antibodies is bound to blue latex particles (detecting antibody). The other antibody is immobilized as a test line on the membrane (catching antibody). The test kit is composed of the sample/conjugate pad, the membrane with test and control lines, and the absorbent pad assembled between plastic films. The upper film contains a test window. When the sample area of the test kit is placed in an extracted sample, the test kit absorbs liquid, which starts to flow up the test kit. 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 red 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 red line, the procedural control line, confirms correct operator performance of the test.