[The value of polymerase chain reaction assay in the diagnosis of intestinal tuberculosis and differentiation from Crohn's disease].

It is difficult to make a precise diagnosis for intestinal tuberculosis and differentiate it from Crohn's disease. For evaluating the efficacy of PCR assay in these two aspects, 36 specimens of intestinal tuberculosis and 26 of Crohn's disease from surgical resections and endoscopic biopsies were subjected to PCR assay. Oligonucleotides derived from IS 6110 sequence, which is a repeated in M. tuberculosis chromosome and highly specific for the M. tuberculosis complex, were used as a primer. The specificity of PCR products was confirmed by digestion with Sal I restrictive endonuclease and southern blot hybridization by using digoxigenin-labeled probe. The results showed that M. tuberculosis DNA was identified in 27 of the 36 specimens of intestinal tuberculosis, but none in those of 26 Crohn's disease. In conclusion, PCR is a rapid, sensitive and specific method for the diagnosis of intestinal tuberculosis, and it is also valuable in differentiating intestinal tuberculosis from Crohn's disease.