Premature rupture of membranes (PROM) constitutes one of the most important dilemmas in the obstetric practice. It could be defined as rupture of membranes before the onset of labor, irrespective of the gestational age.Correct diagnosis of PROM has great importance because failure of diagnosis can lead to unwanted obstetric complications.The false diagnosis of membrane rupture can lead to inappropriate interventions such as hospitalization or induction of labor. Therefore, any biochemical test used to establish a correct diagnosis must be reliable, simple and rapid.