Comparison of the Diagnostic Accuracy of Xpert MTB/RIF and CapitalBio Mycobacterium RT-PCR Detection Assay for Tuberculous Pericarditis

Figures & data

Table 1 Clinical Characteristics of the Included Patients

Characteristics	All (n = 74)	TBP (n = 18)	Non-TBP (n = 56)
Age year (mean ± SD)	59.4 ± 17.1	59.6 ± 19.0	59.3 ± 16.7
Male (n, %)	48 (64.9)	15 (83.3)	33 (58.9)
Systolic pressure (mmHg, mean ± SD)	121 ± 21	115 ± 14	123 ± 23
Diastolic pressure (mmHg, mean ± SD)	76 ± 11	77 ± 10	76 ± 11
Symptoms (n, %)
NYHA class I–II	20 (27.0)	5 (27.8)	15 (26.8)
NYHA class III–IV	54 (73.0)	13 (72.2)	41 (73.2)
Breathlessness	35 (47.3)	9 (50.0)	26 (46.4)
Cough	22 (29.7)	5 (27.8)	17 (30.4)
Edema	2 (3.7)	0 (0.0)	2 (3.6)
Fever	23 (31.1)	8 (44.4)	15 (26.8)
Chest tightness	43 (58.1)	12 (66.7)	31 (55.4)
Pleural effusion	45 (60.8)	11 (61.1)	34 (60.7)
Abdominal effusion	6 (8.1)	4 (22.2)	2 (3.6)
Blood laboratory examinations
Leukocyte (×10^9/L, median, IQR)	5.6 (4.2–7.2)	5.4 (3.3–7.2)	6.0 (4.3–7.4)
Hemoglobin (g, median, IQR)	119 (103–130)	116 (99–127)	120 (103–130)
Platelet (×10^9/L, median, IQR)	206 (167–304)	214 (154–316)	206 (169–305)
ESR (mm/h, median, IQR)	59 (38–77)	64 (50–83)	56 (32–75)
CRP (mg/L, median, IQR)	36.4 (14.6–75.6)	37.3 (28.4–114.5)	36.0 (5.6–74.7)
BNP (ng/L, median, IQR)	98 (60–207)	195 (74–316)	87 (41–169)
Pericardial effusion
ADA (U/L, median, IQR)	29.0 (14.3–58.0)	63.8 (40.4–94.9)	22.1 (12.3–51.8)
LDH (U/L, median, IQR)	598 (241–1170)	1078 (563–1807)	518 (217–924)
Total protein (g/L, median, IQR)	54.5 (47.4–58.6)	52.5 (47.1–57.2)	55.1 (47.7–60.4)
EF (%, median, IQR)	59.4 (56.6–65.2)	59.3 (56.4–62.7)	59.6 (56.7–65.6)

Abbreviations: TBP, tuberculous pericarditis; Hb, hemoglobin; ESR, erythrocyte sedimentation rate; CRP, C reactive protein; BNP, B-type natriuretic peptide; ADA, adenosine deaminase; LDH, lactate dehydrogenase; EF, ejection fraction.

Figure 1 Flow and classification of patients included in this study.

Figure 2 Venn diagram of positive tests for tuberculosis pericarditis patients.

Table 2 The Positive and Negative Rate for Each Index and Reference Test

Test	Tuberculous Pericarditis (n=18)		Non-Tuberculous Pericarditis (n=56)
	Positive (n, %)	Negative (n, %)	Positive (n, %)	Negative (n, %)
MTB culture	18 (100.0)	0 (0.0)	0 (0.0)	56 (100.0)
CapitalBio assay	9 (50.0)	9 (50.0)	5 (8.9)	51 (91.1)
Xpert MTB/RIF	11 (61.1)	7 (38.9)	5 (8.9)	51 (91.1)
Parallel test	13 (72.2)	5 (27.8)	5 (8.9)	51 (91.1)

Abbreviation: MTB, Mycobacterium tuberculosis.

Table 3 Accuracy of CapitalBio Mycobacterium RT-PCR Assay, Xpert MTB/RIF, and Parallel Test for Tuberculous Pericarditis Compared with Culture Using Pericardial Fluid

Test		MTB Culture		Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)	AUC
		Positive	Negative
CapitalBio assay	Positive	9	5	50.0 (26.0–74.0)	91.1 (80.4–97.0)	64.3 (35.1–87.2)	85.0 (73.4–92.9)	0.71 (0.59–0.81)
	Negative	9	56
Xpert MTB/RIF	Positive	11	5	61.1 (35.8–82.7)	91.1 (80.4–97.0)	68.8 (41.3–89.0)	87.9 (76.7–95.0)	0.76 (0.65–0.85)
	Negative	7	56
Parallel test	Positive	13	5	72.2 (46.5–90.3)	91.1 (80.4–97.0)	72.2 (46.5–90.3)	91.1 (80.4–97.0)	0.82 (0.71–0.90)
	Negative	5	56

Abbreviations: MTB, Mycobacterium tuberculosis; PPV, positive predictive value; NPV, negative predictive value; AUC, area under the curve.

Table 4 Comparison of the Diagnostic Accuracy Between Xpert MTB/RIF, The CapitalBio Mycobacterium RT-PCR Detection Assay, and Parallel Test for the Diagnosis of Tuberculous Pericarditis Using Pericardial Fluid

Test	Sensitivity (P-value)	Specificity (P-value)	PPV (P-value)	NPV (P-value)	AUC (P-value)
Xpert vs CapitalBio assay	0.502	1.000	0.796	0.642	0.605
Xpert vs Parallel test	0.480	1.000	0.824	0.585	0.582
CapitalBio assay vs Parallel test	0.171	1.000	0.631	0.316	0.284

Abbreviations: PPV, positive predictive value; NPV, negative predictive value; AUC, area under the curve.