Table 1.

Details of three patients with apparently outlying whole-blood : plasma clozapine ratios (no patient consumed alcohol or used illicit drugs).

Age (years)	Sex	Ethnicity	Smoker	Other drugs	Clozapine dose (mg day−1)	Plasma clozapine (mg l−1)	Plasma nor- clozapine (mg l−1)	Blood clozapine (mg l−1)	Blood nor- clozapine (mg l−1)	Haematocrit
36	F	Caucasian	No	Fluoxetine	275	1.56	0.41	0.60	0.43	0.42
35	F	Caucasian	Yes	Paroxetine, sodium valproate	650	1.85	0.54	0.72	0.77	0.43
41	M	Afro-Caribbean	Yes	Nil	1025	1.73	1.20	0.95	1.36	0.44