[Role of enzyme-linked immunospot assay and tuberculin skin test in the auxiliary diagnosis of initial pulmonary tuberculosis].
OBJECTIVE
To compare enzyme-linked immunospot assay (ELISPOT) and tuberculin skin test (TST) and explore their roles in the auxiliary diagnosis of initial pulmonary tuberculosis.


METHODS
Totally 123 patients with initial pulmonary tuberculosis (tuberculosis group) and 102 patients with non-tuberculosis pulmonary disease (control group) were enrolled. The peripheral blood mononuclear cells of all participants were co-cultured with early secretiny antigen target-6/culture filtrate protein-10 fusion protein (ESAT-6/CFP-10), and spot forming cells (SFCs) were enumerated by ELISPOT (ESAT-6/CFP-10-ELISPOT). TST was also performed simultaneously.


RESULTS
ESAT-6/CFP-10-ELISPOT showed significantly higher numbers of SFCs after stimulation in tuberculosis group than in control group (P = 0.000). The sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, positive predictive value, and negative predictive value of ESAT-6/CFP-10-ELISPOT were 91.1% (111/123), 81.4% (82/102), 4.60, 0.12, 0.85, and 0.87 respectively, while the above values of TST were 65.6% (59/90), 45.1% (46/102), 1.31, 0.76, 0.51, and 0.60, respectively. The sensitivity and specificity of ESAT-6/CFP-10-ELISPOT were significantly higher than those of TST (all P = 0.000). The number of SFCs were not significantly different between smear-positive tuberculosis subgroup and smear-negative tuberculosis subgroup (P = 0.166). The sensitivities were 91.8% (67/73) and 88.0% (44/50) in these two subgroups, respectively, (P = 0.448).


CONCLUSIONS
ESAT-6/CFP-10-ELISPOT may be a more accurate approach for the auxiliary diagnosis of initial pulmonary tuberculosis; meanwhile, it offers certain diagnostic evidences for smear-negative tuberculosis. However, its specificity may be affected by latent tuberculosis infection. On the contrary, TST has poor value in the auxiliary diagnosis of initial pulmonary tuberculosis.
Liu
Fei
F
Department of Tuberculosis, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing 101149, China.
Zhang
Zong-De
ZD
Cao
Min
M
Ma
Li-Ping
LP
Gao
Meng-Qiu
MQ
Wu
Xiao-Guang
XG
Zhu
Li-Zhen
LZ
Ma
Yu
Y
D058501:Enzyme-Linked Immunospot Assay; D006801:Humans; D007963:Leukocytes, Mononuclear; D012680:Sensitivity and Specificity; D014374:Tuberculin Test; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*