Lab on a Chip devices are compact and portable chips mainly constituted by a network of microfluidic channels. They aim at substituting bulk laboratory instrumentations, with the advantages of increasing the automation and the sensitivity of the analysis, reducing the costs and opening the possibility of performing measurements at the Point of Care. Among different Lab on Chips, optofluidic ones have the advantages of optical investigation, but the integration of optical and microfluidic components in a single substrate is very challenging from a technological point of view. A recent fabrication technique, known as femtosecond laser micromachining (FLM), has proven to be ideal for the realization of these devices, allowing the fabrication of the whole device in a single irradiation step. Here, we will present a platelet counter and a microscope on chip, that fully take advantage from the versatility of FLM. To succeed in these works a fundamental aspect to address is the capability to control the sample positioning in the microfluidic channel. A single particle per time should pass in the detection region to avoid the overlooking of specimen. Moreover, a precise control of the sample orientation and position in the channel cross section is needed for imaging. The 3D capabilities of FLM have been fundamental in the realization of advanced fluidic layouts capable of sample manipulation with no need of any additional external field. We have successfully proven red blood cells and platelets counting, as well as single cells, cellular spheroids and drosophila embryos 3D imaging.