Table 2. Results of the multivariable meta-regression model for the characteristics with backward regression analysis (Inverse variance weights; variables were retained in the regression model if P<0.05).

Variables	Coeff.	Std.Err.	P-value	RDOR	[95%CI]
Cte.	4.238	6.4547	0.5405	---	---
S	−0.472	0.3554	0.2417	---	---
Disease	0.612	1.1813	0.6262	1.85	0.09–38.44
Number	0.011	0.0180	0.5818	1.01	0.96–1.06
Specimen source	−0.151	0.6377	0.8222	0.86	0.17–4.43
Instrument	−0.702	1.0401	0.5299	0.50	0.03–7.19
Dye	−0.640	0.5565	0.2728	0.53	0.16–1.77
Lengths	0.009	0.0107	0.4266	1.01	0.98–1.04
Total volume	0.018	0.0648	0.7903	1.02	0.86–‘1.20

Cte: Constant Coefficient; S: Statistic S; RDOR: Relative diagnostic odds ratio.