Semiconductor microlasers are attractive components for micro- analysis systems because of their ability to emit coherent, intense light from a small aperture. By using a surface- emitting semiconductor geometry, we were able to incorporate fluid flow inside a laser microcavity for the first time. This confers significant advantages for high throughput screening of cells, particulates and fluid analytes in a sensitive microdevice. In this paper we discuss the intracavity microfluidics and present preliminary results with flowing blood and brain cells.