Table 2. Passing–Bablok regression analysis comparing the handheld meter (HHM) and the gold-standard (GS) enzymatic colorimetric test.

Parameters	GS enzymatic colorimetric method (mmol/L)	Handheld meter (mmol/L)
Lowest value	0.11	0.10
Highest value	3.94	7.10
Arithmetic mean	1.25	1.90
Median	1.16	1.70
Standard deviation	0.89	1.56
Standard error of the mean	0.057	0.099
Regression equation	HHM = −0.19 + 1.69 GS
Systematic differences
Intercept A	−0.187
95% CI	−0.215 to −0.162
Proportional differences
Slope B	1.691
95% CI	1.657–1.724
Random differences
Residual standard deviation (RSD)	0.137
± 1.96 RSD interval	−0.268 to 0.268
Linear model validity
Cusum test for linearity	Significant deviation from linearity (P < 0.01)
Spearman rank correlation coefficient
Correlation coefficient	0.984
Significance level	P < 0.0001
95% CI	0.979–0.987

Note:

CI, confidence interval.