Table 1.

Clinical chemistry measurements suggested for patients prescribed clozapine¹⁹

Pre-clozapine (baseline evaluation)	After 4 weeks	Four to six monthly	12 months and then annually
Urea and electrolytes, LFTs,* fasting blood glucose or HbA1c,† fasting lipids and cholesterol, creatine phosphokinase activity (CPK)	LFTs,* fasting blood glucose,† fasting lipids and cholesterol	Urea and electrolytes, LFTs,* fasting blood glucose or HbA1c,† fasting lipids and cholesterol	Fasting blood glucose or HbA1c,† fasting lipids and cholesterol

^*Including prothrombin time (international normalized ratio, INR)

^†HbA1c may be a more useful screening test for diabetes during maintenance clozapine therapy (i.e. at 3 months or later) than fasting blood glucose in patients who may not report symptoms of hyperglycaemia. It would not usually be requested more frequently than every 6–8 weeks.