[Mix-up of patient specimen: DNA-microsatellite analysis as a fast identification method].

In a man aged 56 years with dysphagia, an oesophageal biopsy was found to contain an adenocarcinoma. In view of the discrepancy between the clinical and the histological pictures, the biopsy was repeated; in a second biopsy no carcinoma was demonstrable. DNA microsatellite analysis proved that the first biopsy originated from another person. The scheduled oesophageal resection was cancelled and the patient was reassured. A woman aged 77 years underwent gastrectomy because of biopsy samples with adenocarcinoma. However, no tumour was found in the resected stomach. DNA microsatellite analysis showed that the biopsy samples indeed originated from the patient. Unfortunately, mix-up of patient specimens occasionally occurs. Especially a discrepancy between the clinical picture and the histological diagnosis must raise the suspicion of a specimen mix-up. In such cases, DNA microsatellite analysis can give a rapid and reliable answer whether a mix-up has indeed taken place.