Table 2

ISI Calibration results: CoaguChek Mini and RBT/90

	Whole blood			Artificially depleted plasma			Individual coumarin plasma			Pooled coumarin plasma
Centre	N	ISI	CV(b)	N	ISI	CV(b)	N	ISI	CV(b)	N	ISI	CV(b)
The values shown are the ISI derived from the calibration slope b, the CV (%) of the calibration slope, and the number of samples used in the calibration (N). The “Overall” row gives the mean CV(b) and ISI at the 10 centres. The ISI CV% row gives the between centre CV (%) of the ISI. Mean ISI difference (lyophilised plasma ISI – whole blood ISI) and corresponding confidence interval (CI) and p value are provided.
*CV(b) is greater than 3.0 but less than 3.05; †significant displacement at the 1% level using Tomenson’s test.¹³ The absolute % INR deviations from theoretical INR of 2.0 and 4.5, respectively, are given in parentheses. See World Health Organisation guidelines¹¹ for further details.
CV, coefficient of variation; ISI, international sensitivity index; RBT/90, rabbit plain international reference preparation.
1	73	1.63	4.6	68	1.95	3.5 †(46,58)	74	1.73	3.7	13	1.66	15.2
2	74	2.10	3.4	70	2.05	4.0	75	1.79	4.8	13	1.80	14.8
3	70	1.70	3.2	70	1.93	2.4	76	1.75	3.3	13	1.79	4.2
4	76	1.89	3.0*	70	1.96	2.0 †(19,26)	77	1.66	2.4	13	1.71	2.3
5	73	1.78	1.9	70	1.80	1.6 †(21,28)	75	1.72	2.5	12	1.80	2.7
6	77	1.52	4.7	70	1.98	3.1	77	1.91	3.6	13	1.98	6.4
7	75	1.67	2.8	71	1.88	3.9	77	1.80	3.2	13	1.88	5.9
8	73	1.76	2.6	70	1.94	2.8	76	1.81	2.7	13	1.88	5.1
9	71	1.92	3.6	71	1.80	1.4	77	1.73	2.5	13	1.91	3.1
10	71	1.57	3.3	71	1.92	2.0	76	1.79	2.6	13	1.78	3.6

Overall		1.75	3.3		1.92	2.7		1.77	3.1		1.82	6.3
Mean ISI difference					0.17			0.02			0.07
CI				(0.04 to 0.30)			(−0.14 to 0.17)			(−0.08 to 0.22)
p Value					0.02			0.8			0.3
ISI CV (%)		10.0			4.0			3.8			5.2