In the context of an unprecedented aging process, the role of domiciliary care for older adults is becoming increasingly essential. In order to design effective and proactive policies of formal elderly-care, it is crucial to understand how vulnerable elderly individuals would adjust their informal long-term care utilization to changes in the formal-care provision. Although theoretical frameworks have been proposed, showing that a positive relationship could arise when the elderly exhibit an excess demand of care, empirical evidence is scant, due to the lack of credible instruments to account for the endogenous nature of formal-care decisions. We propose a novel instrument, an index that capture individuals' eligibility status to the LTC domiciliary programmes implemented in their own nation or region. That is, a dummy variable - being eligible or not - which is grounded on the LTC regulation context at national or regional level, but still has individual within region variation due to differences in health conditions and vulnerability assessment. We estimate an IV two-part model using a representative sample of the over 60 population for non-institutionalised individuals in Austria, Germany, France and Belgium. Our results, which are robust to a number of different specifications, point at the lack of crowding-out of the informal- by the formal-care, thus suggesting the existence of a substantial unmet demand of LTC among the elderly.