Short communication paths and fast, reliable results are vital for an optimal diagnosis and therapy planning. For this purpose the Knappschaftskrankenhaus Bochum has its own central laboratory. In the laboratory the staff uses high-tech devices to examine tissue samples from organs, bone or skin, body liquids such as blood, serum, plasma, urine, cerebrospinal fluid, or also feces. These analyses have an important part in confirming a diagnosis and monitoring medical therapies. Special importance is placed on the differentiation of leukemia before starting a treatment, stem cell diagnostics and the detection of various different immunosuppressive drugs for patients after a transplantation. The daily MRSA-screenings (to detect multi-resistant germs) with the help of PCR is indispensable. PCR is a polymerase chain reaction, a method with which the hereditary material DNA can be multiplied inside a test tube.