RT Journal Article
SR Electronic
T1 Clinical history and IGRA is unreliable in the diagnosis of tuberculosis
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP p2664
VO 38
IS Suppl 55
A1 William Ricketts
A1 Graham Bothamley
YR 2011
UL http://erj.ersjournals.com/content/38/Suppl_55/p2664.abstract
AB Aim: To monitor the stages in the diagnosis of tuberculosis (TB) and assess whether early interferon-γ responses can be helpful.Method: Site – a TB clinic in a high incidence (58 per 100,000) area of London. 25 patients with suspected TB were followed through their diagnostic process. Patients were scored using a modified UCSD Clinical Suspicion of TB tool by two clinicians blinded to the patient's identity and each other's scores. Estimated risk of TB was made at four stages in the diagnostic process: with clinical data, TST, HIV and IGRA (QuantiFERON Gold in Tube) results; after radiology; sputum smear; and blood tests. A decision as to whether to offer treatment was made at stage two and at each stage thereafter.Results: Clinical history with IGRA was associated with a wide variation in estimated probability of TB (IQR 15-85%). As the diagnostic process progressed, accuracy increased (see figure) and inter-scorer variation decreased. Diagnosis of culture-negative TB was especially problematic. Despite differences between the two scorers there was no difference in the number of patients treated correctly after radiology (69% vs 54% TB; 92% vs 92% not-TB), sputum smear (67% vs 44% TB; 83% vs 92% not-TB) and other blood tests (77% vs 46% TB; 92% vs 92%not-TB).Conclusion: Clinical history even with IGRA results is unreliable in the diagnosis of TB. New tests for culture-negative TB would be valuable.