The papers included in this Review were published between September 2015 and September 2017. The material was compiled using several strategies including extensive searches using Scifinder, Web of Science, PubMed, and Google Scholar. The contents of high impact journals were also scanned, including Analytical Chemistry, Lab-on-a-Chip, Nature, Proceedings of the National Academy of Sciences, Applied Physics Letters, Biosensors and Bioelectronics, Angewandte Chemie, Nano Letters, Science, Biomedical Microdevices, RSC Advances, Electrophoresis, and Langmuir. Several hundred papers relating to the analysis of cells using microfluidics were examined. We have attempted to identify some of the most interesting and promising papers for this Review. Without a doubt, we have missed a few excellent papers and had to eliminate others based on space constraints