IntroductionThe scattering and absorption of light in blood is mostly caused by the red blood cells. Light scattering strongly affects the spectral analysis of blood components. The currently most used standard method to determine the concentration of substances like lactate or glucose in blood samples is the enzymatic-amperometric measuring principle. The goal of our research is the development of an optical measuring setup to determine the concentration of substances with spectral analysis in whole blood samples. To achieve reliable results it is necessary to create a clear optical path. Therefore we compared different methods to determine their performance. MethodsResearch has shown that there are various approaches to separate plasma from the cellular blood components. Most papers describe microfluidic based technologies. In general there are three approaches to successfully fractionate the blood components without centrifugation. One approache is the use of high gradient magnetic fields (HGMS) where the magnetic properties of the blood cells are used. Ultrasound is another way to fractionate the blood components. The ultrasound is used to generate an orthogonal standing wavefield to the flowdirection of the blood cells to focus the cells in the centre of the flow channel. A third approach is dielectrophoresis (DEP) where a strong DEP force traps the blood cells at the elctrodes. The different approaches where theoretical evaluated with regard to there possible results and implementation to reduce light scattering. ResultsThe theoretical evaluation showed that HGMS will provide the best results in regard to reduce the light scattering. It will also be the least complex aproach for the implementation. A demonstration setup was developed which allows it to separate plasma from the cellular blood components. ConclusionHGMS is a possible solution to reduce light scattering in blood samples in order to perfom spectral measurments. The demonstration setup is under further development to create an optical path in an implementable time domain. IntroductionLactate is an important indicator of human metabolism performance. In addition to determine the anerobic threshold for athletes lactate plays a steadily increasing role in clinical medicine. Thus, a fast, reliable and affordable determination is proposed. Up to now measurement of lactate is conducted mostly by enzymatic reactions. One big disadvantage of these reactions is that the used enzymes are not longterm stable. The goal of our research is to develop a method for optical in vitro lactate measurements in practice. Since commercial implementation of FTIR-spectrometers brings some issues, lactate concentration should be determined by using discrete wavelengths. MethodsResearch has shown that optical NIR in vitro determination of lactate is possible, but only with substantial technical and financial effort. We are planning to develop a less complex optical and affordable method to measure lactate concentration. For this purpose we analysed selected blood componen...