Positive predictive value of ELISpot in BAL and pleural fluid from patients with suspected pulmonary tuberculosis

Figures & data

Table 1. Patients’ baseline characteristics.

	Total^a	Observations^b
Number of subjects	56
Male	38 (67.9%)	n = 56
Age	48 [18;84]	n = 56
TB endemic ethnicity^c	35 (63.6%)	n = 55
TB in history	5 (9.3%)	n = 54
Recent travelling to TB-endemic country	22 (59.5%)	n = 37
HIV positivity	0 (0.0%)	n = 32
Immunosuppressive medication^d	2 (3.6%)	n = 56

^a Data are presented as n (%) or median [range].

^b Number of patients in which the variable is known because of missing information in some cases.

^c Defined as countries with an annual TB incidence of >50/100,000.[13]

^d One patient was treated with 5 mg prednisone daily. Another patient was treated with a combination of 15 mg prednisone daily and methotrexate.

HIV: human immunodeficiency virus; TB: tuberculosis.

Table 2. Results of ELISpot in BAL and pleural fluid with respect to the tuberculosis case definition.

	Definite TB (n = 23)	Probable TB (n = 13)	Uncertain TB (n = 5)	No TB (n = 15), including LTBI (n = 11)
Positive ELISpot in BAL (n = 40)	17	7	3	13
Positive ELISpot in pleural fluid (n = 16)	6	6	2	2

BAL: bronchoalveolar lavage; TB: tuberculosis.

Table 3. Results of ELISpot in blood; results of auramine, PCR and culture for MTB in BAL and pleural fluid.

	Definite TB (n = 23)	Probable TB (n = 13)	Uncertain TB (n = 5)	No TB (n = 15), including LTBI (n = 11)
ELISpot blood
Positive	23	12	3	11
Negative	0	1	2	4
Auramine
Positive	5	0	0	1
Negative	18	13	5	14
PCR for MTB
Positive	13	0	0	0
Negative	10	13	5	14^a
Culture for MTB
Positive	21	0	0	0
Negative	2	13	5	15

^a One missing PCR result.

MTB: Mycobacterium tuberculosis; PCR: polymerase chain reaction; TB: tuberculosis.

Figure 1. Ratio between SFCs in BAL (black dots) respectively pleural fluid (red dots) and SFCs in blood (y-axis, scale log 10), with respect to the tuberculosis (TB) case definition (x-axis). Results of ESAT-6 (a) and CFP-10 (b) are shown separately. In patients with no active TB, patients with LTBI (filled dots) and without LTBI (open dots) were represented separately.

Figure 2. PPV of ELISpot in BAL fluid (a) and pleural fluid (b) (first column) together with the added value of cut-off >1.0 for the ratio between the extra-sanguineous and systemic interferon-gamma responses in the CFP-10 panel (second column), in the ESAT-6 panel (third column), in at least one of the two panels (fourth column) and in the ESAT-6 and CFP-10 panel simultaneously (fifth column).