A method is taught for the accurate determination of the premature rupture of membranes (PROM), defined as spontaneous rupture of membranes before the onset of uterine contractions. More specifically, a lateral flow assay strip tests for at least two antigens to greatly limit or eliminate the possibility of false negatives. A built-in timer in the cassette holding the lateral flow assay further increases the accuracy of the test. A collection buffer vial with self-contained shipping and dropper caps and built-in stand is also taught.