Table II.

Relevant clinical values of blood cobalt (Co) and their relationship to the volumetric bearing surface wear rate of the metal-on-metal joint (CI, confidence interval)

Whole blood Co (µg/l)	95% CI rate of wear (mm3/year)
0.5	0.47 to 0.64
1	0.77 to 1.16
2	1.26 to 2.10
3	1.68 to 2.96
4	2.07 to 3.79
5	2.43 to 4.58
10	4.00 to 8.28
15	5.35 to 11.7
20	6.58 to 14.9
30	8.80 to 21.1
40	10.8 to 27.01
50	12.7 to 32.7
100	20.9 to 59.0
150	28.0 to 83.4
200	34.4 to 107
250	40.3 to 129
300	46.0 to 151