Investigating renal function during lithium treatment.

The tests that have been used to assess glomerular and tubular function in patients receiving treatment with lithium have been reviewed. The advantages and disadvantages of these are discussed. The most useful tests are the creatinine clearance, which may be predicted from the serum creatinine using a formula or nomogram, and the measurement of urine osmolality, followed if necessary by assessment of the maximum urine concentrating ability after desamino cys-1-8-D arginine vasopressin.