A candidate reference method for serum calcium measurement by inductively coupled plasma mass spectrometry

作者：Yan, Ying; Ge, Menglei; Ma, Rong; Zhao, Haijian; Wang, Donghuan; Hu, Cuihua; Wang, Jing; Chen, Wenxiang; Zhang, Chuanbao^*

来源：Clinica Chimica Acta, 2016, 461: 141-145.

DOI：10.1016/j.cca.2016.07.004

• Serum
• Calcium
• Aluminum
• Inductively coupled plasma mass spectrometry (ICP-MS)
• Reference method

Background: Calcium is an important serum ion which is frequently assayed in clinical laboratories. Since quality assurance requires reference methods, the establishment of a candidate reference method for serum calcium measurement is important.
Method: An inductively coupled plasma mass spectrometry (ICP-MS) method was developed. Serum samples were spiked gravimetrically with aluminum internal standard, digested with 69% ultrapure nitric acid and diluted to test concentration. Then the Ca-44/Al-27 ratios were measured by ICP-MS in hydrogen mode. The method was calibrated using 5% nitric acid matrix calibrators and the calibration function was established with bracketing method.
Results: The correlation coefficients between the measured Ca-44/Al-27 ratios and the analyte concentrations ratios were all >0.9999. The coefficients of variation of the measurements were 0.27% and 0.16% for two spiked serum. The analytical recovery was 100.24%. The accuracy of the measurement was also verified through measurement of certified reference materials. Comparison with recognized reference method and international inter laboratory comparisons gave satisfied results.
Conclusion: New ICP-MS method is specific, precise, simple, and low in cost, and may be used as a candidate reference method in the standardization of serum calcium measurement.

• 出版日期2016-10-1
• 单位北京医院