Xpert Ultra and TrueNat MTB plus assays for the diagnosis of gastrointestinal tuberculosis: A diagnostic accuracy study

Table 1 Baseline data of patients included in the study, n (%)

Clinical features	GITB (n = 26)	Controls (n = 12)	P value
Age, mean ± SD	42.2 ± 17.8	36.4 ± 9.14	0.30
Male gender	13	8	0.48
Abdominal pain	20 (76.9)	10 (83.3)	1.00
Diarrhea	6 (23.1)	6 (50)	0.14
Albumin (mg/dL)	3.73 (3.4-4.13)	3.94 (3.59-4.41)	0.43
Fever	13 (50)	3 (25)	0.18
Loss of appetite	15 (57.7)	7 (58.3)	1.00
Loss of weight	21 (80.7)	7 (58.3)	0.23
History of TB	1 (4)	2 (16.6)	0.22
Family history of TB	7 (27)	2 (16.6)	0.68

TB: Tuberculosis; GITB: Gastrointestinal tuberculosis.

Table 2 Basis of diagnosis for patients included in the study

		GITB (n = 26)	Controls (n = 12)
Microbiology	Acid-fast bacilli smear	1	0
	Acid-fast bacilli culture	3	0
Histopathology-granuloma		4	1-granuloma; 2-amoebiasis
Response to antitubercular therapy		23	4 (no response) and response to Crohn’s disease therapy; 6 (improvement with Crohn’s disease therapy)

GITB: Gastrointestinal tuberculosis.

Table 3 Diagnostic accuracy of Xpert Ultra and TrueNat MTB Plus, % (95% confidence interval)

		Sensitivity	Specificity	PPV	NPV	Accuracy
Xpert Ultra	Definite GITB	66.67 (9.4-99.2)	83.33 (51.6-97.9)	50 (18.3-81.7)	90.91 (66.4-98)	80 (51.9-95.7)
	Probable GITB	65.22 (42.7-83.6)		88.24 (67.2-96.5)	55.56 (40.4-69.8)	71.43 (53.7-85.4)
	Overall	65.38 (44.3-82.8)		89.47 (69.9-96.9)	52.63 (38.2-66.6)	71.05 (54.1-84.6)
TrueNat MTB Plus	Definite GITB	66.67 (9.4-99.2)	50 (21.1-78.9)	25 (11.1-47)	85.71 (52.4-97)	53.33 (26.6-78.7)
	Probable GITB	56.52 (34.5-76.8)		68.42 (52.6-80.9)	37.5 (22.4-55.5)	54.29 (36.7-71.2)
	Overall	57.69 (36.9-76.7)		71.43 (56.5-82.8)	35.29 (20.9-52.9)	55.26 (38.3-71.4)

GITB: Gastrointestinal tuberculosis; PPV: Positive predictive value; NPV: Negative predictive value.