title: Clinical evaluation of Gen-Probe's amplified mycobacterium tuberculosis direct test for rapid diagnosis of Mycobacterium tuberculosis in Egyptian children at risk for infection.
abstract: BACKGROUND
  Diagnostic detection of tuberculosis (TB) has improved considerably. Available, standardized, nucleic acid-based amplification techniques have been shown to yield reliable results within 4 to 7 hours of sample processing.
  
  
  OBJECTIVE
  To study the diagnostic performance of Gen-Probe's technique for direct detection of Mycobacterium tuberculosis in comparison with BACTEC 460 TB culture for both positive and negative Ziehl-Neelsen smears in Egyptian children at risk for TB infection.
  
  
  METHODS
  We prospectively evaluated 50 children from families with a positive history of TB. All patients were referred from outpatient clinics of the Mansoura University Children's Hospital, Egypt. The children had a positive tuberculin skin test with an induration diameter of more than 10 mm and had scars from a bacille Calmette-Guérin vaccination within the past 2 years. Three consecutive sputum samples were taken from each patient. The samples were examined to detect M. tuberculosis by means of the Gen-Probe technique, direct smear microscopy, and bacterial culture by BACTEC 460 TB.
  
  
  RESULTS
  Of the 50 cases, 30 (60%) had sputum samples that were positive for TB by BACTEC 460 TB culture, and 29 cases (58%) were positive by the Gen-Probe technique. Sensitivity and specificity of Ziehl-Neelsen smears was 83.3% and 100%, respectively, with overall accuracy of 90%. Sensitivity and specificity of the Gen-Probe technique were 96.7% and 100%, respectively, with overall accuracy of 98%.
  
  
  CONCLUSIONS
  The results of this study suggest that the Gen-Probe technique is an accurate method for rapid detection of M. tuberculosis complexes in respiratory samples from children at risk for TB. It can be used for diagnosis of smear-negative cases that are suspect for TB.
authors.affiliation: Egypt-Mansoura University, Faculty of Medicine, Department of Clinical Pathology, Mansoura 65 Egypt. may_s65@hotmail.com
authors.forename: Maysaa
authors.initials: M
authors.lastname: el-Sayed Zaki
authors.forename: Samir
authors.initials: S
authors.lastname: Abou-el Hassan
mesh_terms: D000293:Adolescent; D001431:Bacteriological Techniques; D002648:Child; D015342:DNA Probes / Q000737:chemistry; D004534:Egypt; D005260:Female; D005784:Gene Amplification; D006801:Humans; D008297:Male; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D011446:Prospective Studies; D012329:RNA, Bacterial / Q000032:analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology; D014374:Tuberculin Test; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000382:microbiology*
chemical_list: D015342:DNA Probes; D012329:RNA, Bacterial