[Utility value of a T-cell interferon-γ release assay based on recombinant Mycobacterium tuberculosis 11kD protein in the diagnosis of tuberculosis].

OBJECTIVE

To evaluate the diagnostic efficiency of a T-cell interferon-γ release assay based on recombinant Mycobacterium tuberculosis (MTB) 11kD protein for diagnosing tuberculosis.

METHODS

This prospective study enrolled inpatients with suspected tuberculosis at PUMCH to examine the diagnostic sensitivity, specificity, predictive value (PV) and likelihood ratio (LR) of T-cell interferon-γ release assays based on recombinant MTB-11kD protein, early antigenic target-6 (ESAT-6) and culture filtrate protein-10 (CFP-10) peptides (T-SPOT. TB). Test results were compared with final clinical and microbiological diagnoses.

RESULTS

Among 151 inpatients with suspected tuberculosis, 33 (21.9%) were microbiologically or clinically diagnosed as tuberculosis and 107 (70.9%) ruled out. And the remaining 11 (7.3%) patients were clinically indeterminate. The sensitivities of recombinant MTB-11kD-ELISPOT assay and T-SPOT. TB were 60.6%and 81.8%respectively (P = 0.057).Whereas, the specificity of recombinant MTB-11kD-ELISPOT assay was significantly higher than that of T-SPOT. TB (84.1%vs 72.9%, P = 0.046). The parallel testing increased the sensitivity to 84.9% and serial testing increased the specificity to 86.9%.

CONCLUSION

The recombinant MTB-11kD-ELISPOT assay is more specific than T-SPOT. TB. And its combination with T-SPOT. TB may improve the diagnostic efficiency for tuberculosis.