Assessment by meta-analysis of interferon-gamma for the diagnosis of tuberculous peritonitis

Table 1 Summary of included studies

Ref.	Patients	Assay method	Cut off	Test results				Quality score
				TP	FP	FN	TN	STARD	QUADAS
Ribera et al[12]	86	RIA	3 U/mL or 9 U/mL	16	0	0	70	11	9
Soliman et al[13]	50	ELISA	26 pg/mL	13	0	3	33	15	12
Sathar et al[14]	92	RIA	3.2 U/mL	25	1	2	54	13	10
Saleh et al[28]	41	ELISA	0.35 IU/mL	13	0	1	27	16	11
Sharma et al[29]	119	ELISA	112 pg/mL	30	3	1	85	18	13
Sathar et al[30]	52	ELISA	20 pg/mL	21	0	2	29	14	12

ELISA: Enzyme-linked immunosorbent assay; RIA: Radioimmunoassay; TP: True-positive; FP: False-positive; FN: False-negative; TN: True-negative; STARD: Standards for Reporting Diagnostic Accuracy, maximum score 25, guidelines that aim to improve the quality of reporting in diagnostic studies; QUADAS: Quality Assessment for Studies of Diagnostic Accuracy, appraisal by use of empirical evidence, maximum score 14, expert opinion and formal consensus to assess the quality of primary studies of diagnostic accuracy.

Table 2 Characteristics of included studies

Ref.	TB/N-TB patients	Reference standard	Cross-sectional design	Consecutive or random	Blinded design	Prospective
Ribera et al[12]	16/70	Bac/His or Clin	No	Yes	No	Yes
Soliman et al[13]	17/33	Bac/His or Clin	No	Yes	Yes	Yes
Sathar et al[14]	30/62	Bac/His	No	Yes	No	Yes
Saleh et al[28]	14/27	Bac/His or Clin	No	Yes	No	Yes
Sharma et al[29]	31/88	Bac/His	Yes	Yes	Yes	Yes
Sathar et al[30]	23/29	Bac/His or Clin	No	Yes	No	Yes

TB: Tuberculosis; Bac: Bacteriology; His: Histology; Clin: Clinical course.

Table 3 Weighted meta-regression of the effects of study design methods and methodological quality on diagnostic accuracy of interferon-gamma assays

Covariate	Studies	Coefficient	RDOR (95%CI)	P
Consecutive or random	6	-	-	-
Prospective	6	-	-	-
Cross-sectional design	1	-1.763	0.17 (0.00, 2053.55)	0.593
Blinded design	2	-0.649	0.52 (0.01, 31.46)	0.649
Methods
RIA	2	-0.815	0.44 (0.01, 26.58)	0.571
ELISA	4
QUADAS ≥ 10	5	-2.137	0.12 (0.00, 98.54)	0.387
STARD ≥ 13	5	-2.137	0.12 (0.00, 98.55)	0.387

ELISA: Enzyme-linked immunosorbent assay; RIA: Radioimmunoassay; STARD: Standards for Reporting Diagnostic Accuracy, maximum score 25, guidelines that aim to improve the quality of reporting in diagnostic studies; QUADAS: Quality Assessment for Studies of Diagnostic Accuracy, appraisal by use of empirical evidence, maximum score 14, expert opinion and formal consensus to assess the quality of primary studies of diagnostic accuracy; RDOR: Relative diagnostic odds ratio.