Table 2.

Agreement among laboratories before and after use of agreed protocol

Sample analyzed	Before	After
	ICC	ICC	within-laboratory variance	between-laboratory variance
Food	0.61	0.79	0.042 (0.204)	0.013 (0.115)
Plasma	0.51	0.82	0.000 (0.004)	0.000 (0.009)
Saliva	0.72	0.90	0.047 (0.218)	0.001 (0.034)
Standard solutions (direct analysis)	0.90	0.93	0.003 (0.001)	0.001 (0.002)
Standard solutions (diffusion analysis)	0.89	0.90	0.003 (0.001)	0.001 (0.003)
Urine	0.52	0.85	0.198 (0.445)	0.022 (0.149)

n = 15 per laboratory. Standard deviations are given in parentheses.