Insulin-like growth factor binding protein-1, a quick way to detect amniotic fluid

The detection of premature rupture of membranes (PROM) is essential to the management of pregnancy. Various tests, all with different limitations, have been used to diagnose PROM. Insulin-like growth factor binding protein-1 (IGFBP-1) is present in an essentially higher concentration in amniotic fluid, than in serum, cervical mucous, urine and seminal plasma. A commercial kit, with monoclonal antibodies to IGFBP-1 attached to a stick, is available. The aim of this study was to investigate whether a rapid dipstick test could confirm or exclude the presence of amniotic fluid.

A multicenter study, involving six departments of obstetrics and gynecology in Sweden, was designed to evaluate the new dipstick technique of diagnosing the presence of amniotic fluid in the vagina. One hundred and seventy-four women were examined. Forty-six women with obvious PROM, 29 women without PROM and 99 women with suspected PROM.

Forty-four out of forty-six women with obvious PROM had a positive PROM-TEST. Twenty-seven out of twenty-nine women without PROM had a negative PROM-TEST, giving a sensitivity of 95.7% and a specificity of 93.1%. Among the women with suspected rupture of membranes, the sensitivity was 70.8%, the specificity 88.2% and the positive predictive value (PPV) 92%.

IGFBP is present in high concentration in amniotic fluid. The dipstick test with monoclonal antibodies to IGFBP-1 is rapid and has a high PPV, sensitivity and specificity. It is a useful complement to the existing arsenal of tests to detect PROM.