Which test is NOT used for assessing rupture of membranes?

The measurement of cervical dilation is not used to assess the rupture of membranes. This assessment typically evaluates the opening of the cervix in preparation for labor, focusing on the stage of cervical effacement and dilation rather than the integrity of the membranes.

In contrast, the other methods listed are specifically designed for evaluating whether the membranes have ruptured. The Nitrazine test detects the pH of vaginal fluid, which changes if amniotic fluid is present, as it has a higher pH compared to normal vaginal secretions. The fluid pooling exam involves assessing for the presence of amniotic fluid in the vaginal canal, and ferning microscopy examines the dried vaginal fluid for a characteristic 'ferning' pattern, which is indicative of amniotic fluid. Each of these tests provides information directly related to the status of the membranes, making cervical dilation measurement the outlier in this context.