[Etiological diagnosis of tuberculous lymphadenitis by polymerase chain reaction]

By using polymerase chain reaction (PCR) technique in amplifying a reparative DNA sequence specific for Mycobacterium tuberculosis, the pathogenic bacterium in paraffin-embedded tissue was identified. A 123-base-pair fragment, specific PCR product, was obtained from all 12 cases of tuberculous lymphadenitis and 4 out of 10 cases in which tuberculosis was suspected. In the 4 suspected cases, 3 cases showed good results when treated by anti-tuberculosis therapy. The remaining case was lost from follow-up. Comparing acid-fast stain and PCR results, we confirm that PCR method is more powerful and more sensitive than acid-fast stain in the etiological diagnosis of tuberculous lymphadenitis.