Lithium test-dose methodology using flame photometry: problems and alternatives.
Two published methods of assessing test-dose 24-hour serum lithium concentrations as measured by flame emission spectrophotometry were compared in 17 patients. The first method was unsuccessful in predicting required maintenance dosage in 53% of patients studied. By applying the second methodology, a strong positive correlation (r = 0.69) was obtained between the reciprocal of the maintenance dose required to achieve a steady-state serum lithium concentration of 1.0 mEq/L and the test-dose 24-hour serum lithium level. Problems relating to the use of flame photometry to measure serum lithium concentrations less than 0.05 mEq/L are discussed.
D000328:Adult; D000368:Aged; D001702:Biopharmaceutics; D003866:Depressive Disorder / Q000097:blood / Q000188:drug therapy*; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008094:Lithium / Q000008:administration & dosage / Q000097:blood* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D010783:Photometry / Q000295:instrumentation / Q000379:methods*
D008094:Lithium