CRP, or C-reactive protein, is a so-called acute-phase protein produced by the liver in response to inflammation, tissue destruction and infection. The CRP test detects this protein in the blood. In bacterial infections the CRP level can often rise to 100 mg/l or more, while in viral diseases it is much lower, usually only up to 10-40 ml/l. The CRP rapid test was developed to support clinical decision-making. It helps the doctor to distinguish between viral and bacterial infections and to decide on the treatment. Antibiotics do not help in viral infections, while bacterial infections usually require treatment with antibiotics.