According to various embodiments, a microfluidic system for detecting a biological entity in a sample volume is provided. The microfluidic system may include: a chamber configured to receive the sample volume, wherein the chamber includes a detection region for detecting the biological entity; a first port in fluid communication with the chamber; and a second port including a filter in fluid communication with the chamber; and wherein a fluid provided to the first port or the second port flows between the first port and the second port through the chamber.