Is it NICE to monitor lithium routinely?

Lithium has a narrow and well described therapeutic range.

The aim of this study was to evaluate lithium blood concentration monitoring in Canterbury District Health Board (CDHB) and consider whether it meets the UK National Institute for Health and Clinical Excellence (NICE) standard (in lieu of more local standards).

Lithium dispensing data for patients within the CDHB boundaries was combined with lithium blood concentrations for the period of 1 July 2009 to 30 June 2010 and the results analysed.

Lithium was prescribed for 1416 patients with a mean daily dose of 507 mg per day. 92% of patients in CDHB had had a lithium blood concentration performed at least once during the year. Twenty percent had had four or more lithium blood concentrations analysed. The mean (plus or minus 95% CI) lithium blood concentration was 0.63 (0.62 to 0.64) mmol/L; the median (interquartile range) was 0.6 (0.43 to 0.80) mmol/L and the range was 0 to 2.8 mmol/L. The median (interquartile range) sampling interval was 35 (13-93) days. Sampling was performed approximately every 3 months (80 to 100 days) in 11 patients (<1%). Of those 56 patients that had a lithium blood concentrations >1.2 mmol/L only 7 patients had this repeated within 3 weeks.

In conclusion, lithium blood monitoring at CDHB did not achieve the NICE standard. This is in keeping with a number of other audits conducted of lithium blood monitoring.