[The PCR in gastroenterology].

The polymerase chain reaction (PCR) is a molecular biology technique that can significantly amplify DNA or RNA. With the use of recombinant DNA technology, PCR has allowed a spectrum of advances in diagnostic pathology, specially in the fields of viral diseases, hematology and genetic diseases. This work describes the basic aspects, as well as specific issues of the PCR technique. It also contains protocols and experimental conditions that are being used in our laboratory in the diagnosis of hepatitis B (HBV), hepatitis C (HCV) and in the amplification of specific sequences of the APC gene.