A diagnostic algorithm for tuberculous pleurisy using the ELISPOT assay on peripheral blood and pleural effusion

초록

Background: Diagnosis of tuberculous (TB) pleurisy remains challenging due to the paucibacillary nature of the disease. We prospectively assessed the diagnostic usefulness of the T-cell based ELISPOT assay, and created a clinical algorithm for differentiating TB pleurisy from other diagnoses. Methods: All adult patients with suspicion for TB pleurisy were enrolled in a tertiary hospital in Seoul, South Korea, over a 7-year period. ELISPOT assays were performed using mononuclear cells from peripheral blood and pleural effusion. Results: Seventy-seven patients with suspected TB pleurisy were enrolled. Of these, 33 (43%) patients, comprising 27 confirmed and 6 probable TB pleurisy, were classified as TB pleurisy, and 36 (47%) were classified as not TB. The remaining 8 with possible TB pleurisy were excluded from the final analysis. The sensitivities and specificities, respectively, of the diagnostic methods were as follows: pleural fluid adenosine deaminase (ADA) level 32U/L, 81% and 79%; peripheral blood mononuclear cells (PBMC) ELISPOT assay, 82% and 73%; pleural effusion-mononuclear cells (PE-MC) ELISPOT assay, 58% and 87%. When the diagnostic algorithm was applied, PBMC ELISPOT >= 6 spots or ADA >= 32U/L' as a rule-out test safely excluded 46% (12/26) of the not TB patients, and PE-MC >= 6 spots' as a rule-in test accurately classified 23% (7/31) of the patients with TB pleurisy. Conclusions: A diagnostic algorithm combining ELISPOT assays and ADA levels in pleural fluid appears to be a promising and non-invasive approach for patients with suspected TB pleurisy.

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