"The goal of ""InstantCount"" is to develop low-cost point-of-care blood tests based on microfluidic counting chambers and image cytometry (InstantCount tests) for use in challenging environments, e.g. remote areas in developing countries.Preliminary work on CD4 counting (measuring the concentration of helper T-cells in blood in order to diagnose the progression of an HIV infection) demonstrates the feasibility of the concept.I have assembled a prototype instrument for large area fluorescence imaging, developed the image analysis software and microfluidic counting chambers containing dried reagents. The fabrication of these chambers is simple and the used materials cheap, making affordable diagnostics even in the poorest regions appear feasible.However, a clinical evaluation of the tests outside the laboratory environment in rural areas requires improved reproducibility in the fabrication of the chambers, which would also enable the development of new assays, once the properties of the reagent layers can be tailored according to the requirements of different tests.I propose the development of printing techniques for the fabrication of InstantCount tests. Counting chambers with precisely defined thickness will be realised by printing of microbeads embedded in glue. Printing of different types of hydrogel will offer solutions like self-sealing chambers or timed release of reagents with a wide range of molecular sizes without the need for mixing other than by diffusion.With these techniques, we will realise rapid low-cost point-of-care diagnostics for primary health care in remote areas and small medical practices. Complete blood counts for general health screening, CD4 counting and the detection of parasites in red blood cells such as in malaria will be provided.The project will neither require expensive fabrication methods in clean room facilities nor high-resolution optics in the instruments.Printing can bridge the gap between prototyping and production."