Since the Lab on a Chip concept was introduced in the 1990s, a lot of scientific advancements have occurred. However, large scale commercial realization of microfluidic technology is being prevented by the lack of standardization. There seems to be a gap between Lab on a Chip systems developed in the lab and those that are manufacturable on a large scale in a fab. In this paper, we propose a modular platform which makes use of standardized parts. Using this platform, a functional-based method of designing microfluidic systems is envisioned. To obtain a certain microfluidic function, a bottom-up design is made. This results in micro fluidic building blocks that perform a microfluidic function. This microfluidic building block is then stored in a library, ready for reuse in the future. Key characteristics are shown for several basic microfluidic building blocks, developed according to a footprint and interconnect standard by various players in the microfluidic world. Such a library of reusable and interoperable microfluidic building blocks is important to fill the gap between lab and fab, as it reduces the time-to-market by lowering prototype time cycles. The wide support of key European players active in microfluidics, which is shown by an ISO workshop agreement (IWA 23:2016), makes this approach more likely to succeed compared to earlier attempts in modular microfluidics.