title: Evaluation of a new lithium colorimetric assay performed on the dade behring dimension X-pand system.
abstract: Lithium is the standard first line of treatment for bipolar disorder. Because of its potential toxicity, levels of the drug have to be constantly monitored. To this end, an accurate and rapid assay is thus required. Moreover, lithium measurement allows differential diagnosis in patients with hallucinations, dementia and amnesia. The lithium concentration in blood is usually evaluated by flame photometry, atomic absorption spectroscopy or ion selective electrode. The aim of this study was to evaluate the analytical performance of a new colorimetric assay for lithium. Within-day precision of a pool with a target value of 1.25 mmol/l was 2.18% (CV) and day-to-day precision was assessed using serum aliquots containing two concentrations of lithium, and CVs were 5.47 and 1.6% at 0.6 and 1.15 mmol/l, respectively. The lower detection limit (LLD) was <0.08 mmol/l. The assay seemed to be linear up to 5 mmol/l. Results of a comparison method using Deming regression were: y=1.161x-0.0075 (r=0.9879) for regression with the Flame Photometer and y=0.9729 x+0.0133 (r=0.9787) for regression with atomic absorption spectroscopy. Moreover, in this study we did not find any interference with drugs or other analytes tested. In conclusion, this assay may be a method of choice for measuring lithium blood concentrations, especially in emergency situations.
authors.affiliation: Laboratoire de Biochimie 1, CHU de Bicêtre, AP-HP, Le Kremlin Bicêtre, France.
authors.forename: Damien
authors.initials: D
authors.lastname: Gruson
authors.forename: Abdelkrim
authors.initials: A
authors.lastname: Lallali
authors.forename: Valérie
authors.initials: V
authors.lastname: Furlan
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: Taburet
authors.forename: Alain
authors.initials: A
authors.lastname: Legrand
authors.forename: Marc
authors.initials: M
authors.lastname: Conti
mesh_terms: D018692:Antimanic Agents / Q000097:blood*; D001331:Automation; D002138:Calibration; D003124:Colorimetry / Q000379:methods; D004632:Emergency Medical Services; D006801:Humans; D016651:Lithium Carbonate / Q000097:blood*; D012044:Regression Analysis; D015203:Reproducibility of Results; D013054:Spectrophotometry, Atomic
chemical_list: D018692:Antimanic Agents; D016651:Lithium Carbonate