Monitoring of lithium therapy

Results of serum lithium performed in the Chemical Pathology Laboratory, Universiti Kebangsaan Malaysia, Kuala Lumpur, over a years' period (June 1991 till May 1992) formed the subject of study. A total of 277 tests were carried out on 148 patients, giving a frequency of about 23.1 tests per month. Complete data regarding age, sex and ethnic group was available for 140 subjects. There were 74 males and 66 females. Racial distribution was 72 Malays, 42 Chinese and 26 Indians. Their ages ranged from 15 to 80 years. One hundred and twenty-three subjects (87.6%) were within the 3rd to 5th decade of life. 136/277 (49.1%) of serum lithium levels were less than 0.6 mmol/l and 24/277 (8.7%) gave results greater than 1.0 mmol/l. Only 6 tests gave values which exceeded 2 mmol/l. This study reveals the need to conduct a prospective study to determine the underlying cause of the high incidence of low serum lithium levels and whether this situation is associated with a satisfactory treatment response in the said population.