Table 1.

The effects of anaemia and acidosis on bias and limits of agreement

		Haemoglobin concentration (g/dl)			Hydrogen ion concentration (nmol/l)
	Total	<8	8–12	>12	25–63	>63
n (measurements)	1132	49	963	120	1064	58
Bias	1.34	2.09*	1.37*	0.72†‡	1.39	0.38§
Upper limit	4.97	7.04	4.87	4.37	4.95	4.61
Lower limit	-2.29	-2.79	-2.14	-2.93	-2.18	-3.85

P < 0.01, versus *haemoglobin >12 g/dl, ^†haemoglobin <8 g/dl, ^‡haemoglobin 8–12 g/dl and ^§hydrogen 25–63 nmol/l.