Comparison of spectrophotometric and ICP-MS methods in serum lithium level measurement

Aim: Lithium is an important trace element. It is widely used in the treatment of bipolar patients and because its therapeutic window is narrow and there are no specific clinical factors and properties for lithium poisoning, an appropriate method must be found. In order to trace lithium level in the blood and maintain it consistently, an appropriate calibration method must be available. For this reason, the concentration of lithium in the blood must be measured in a safe, stable and repeatable manner. For this reason, it must produce an analytical method that gives accurate and precise results. For this purpose, in the past, absorbsion and emission spectrophotometri (FAES AND FAAS) were used and then the use of ISE and Spectrophtometric methods started to arise. In the analysis of the trace elements, one of the most sensitive and referential methods is the ICP-MS method. However, when we think in terms of costings, this method can't be found in routine laboratories. In our research, we will make a comparison of ICP-MS and Spectrophtometric methods. And in routine and clinical laboratories compared to the Spectrophtometric method, does it give valid results or not. Metrial and Method: In order to measure lithium, 50 samples were sent to the laboratory. After working on the automatic analysis device found in the laboratory using the method of Spectrophtometric, the samples were sent to the main laboratory in the University of Degla for measuring lithium using ICP-MS method and then the results of the two methods were discussed and compared. We analyzed the results by comparing method and their precision, and recovery. The comparison data was validated by Regrasion analysis. In order to assess the absolute proportionality between the two methods, we used the Bland Altman methods. In order to show the proportional relationship between the two methods, we used Passing Bablok analysis. Results: In the linearite process, the linear range is found between (5-0.156 mmol / L). Because the proportional values % recoveries are more than 95%, linearite is within acceptable limits. For repeatability within day and day to day repeatability we took two different standard samples (mean 0.97 and 1.75 mmol / L). Concerning 0.97mmol / L the repeatability concentration within the day and between days CV% value were 2.09% and 3.68 respectively. Concerning 1.75mmoL / L repeatability within the day and between days CV value% were 2.28% and 4.06% respectively. Less than 10% was found to match the standard values. For the recovery process, the mean of the % Recovery values reached 96%, and the relative error of 4% was found appropriate for normal values. The regression coefficient was r = 0.963. In both methods, it was in a proportional and consistent level. Conclusion: In our research we found that analytical amounts of the spectrophtometric method are sufficient and in clinical biochemistry laboratories, it gave results safely and effectively. Key Words: Lithium, ICP-MS, Spectrophotometric, Bipolar disorder