In prelabour rupture of membranes (PROM) or preterm PROM the amniotic membranes rupture prior to labour. Where this is not overt a speculum examination is undertaken to confirm diagnosis. The Vision Amniotic Leak Detector (ALD) is a panty liner that can diagnose amniotic fluid as a cause of vaginal wetness. It was evaluated by the UK National Institute for Health and Care Excellence (NICE) as part of the Medical Technologies Evaluation Programme. The sponsor (CommonSense Ltd) identified five studies, of which three were deemed within scope by the External Assessment Centre (EAC). Two of these three used an inappropriate comparator. The EAC recalculated the diagnostic accuracy of Vision ALD using speculum examination as the comparator: sensitivity of 97% (95% CI 93-99%), negative predictive value of 96% (95% CI 92-98%). A negative result would therefore allow patients to be discharged with confidence. In the sponsor's cost-consequence model only patients with a positive Vision ALD result would have a speculum examination, producing a cost saving of around £10 per patient. The EAC felt that some costs were unjustified and the model did not include infection outcomes or use in a community setting. The EAC revised the sponsor's model and found the results were most sensitive to clinician costs. Vision ALD was associated with savings of around £15-£25 per patient when administration in lower-cost community healthcare avoided a referral to a higher-cost secondary-care centre. NICE published guidance MTG15 in July 2013 recommending that the case for adopting Vision ALD was supported by the evidence.