Detection of cocaine on the level of a few ng/ml by the use of lab-on-a-paper test co-working with OLED light source as exciatation light source and CCD-based detection unit is described in this paper. The new method enables not only yes or now answer of drug presence in a tested sample but also concentration of the drug in the sample. Presented here results opens a new way toward portable instrumentation for point-of-care detection of cocaine (and in the future other drugs) in sweat of for example professional drivers. This device will be a drug-tester similar to widely now used alcohol testers.