Simultaneous Determination of Steroid and Vitamin D by LCMS/MS
Shailesh Damale,
Assistant Manager,
Shimadzu Analytical (India) Pvt Ltd
Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has seen enormous growth in clinical laboratories during the last 10–15 years. It offers analytical specificity superior to that of immunoassays or conventional high performance/pressure liquid chromatography (HPLC)
LC/ MS/MS has become the standard for assay of steroid hormones for diagnosis of endocrine disorders. Vitamin D analysis by LC/MS/MS is widely used in the clinical laboratory today. Whereas immunoassays are unable to distinguish between 25-hydroxy vitamins D2 and D3, the LC/MS methodologies are able to measure these levels separately so the contribution of each to the total can be determined.
Limitations of immunoassays such as nonspecific binding of the antibody and cross-reactivity with metabolites that often result in overestimation have made the more accurate LC/MS/MS methodologies the assays of choice
However, several limitations of LC-MS/MS have become apparent, centring on the interacting triangle of sensitivity – specificity – throughput. While sample throughput is higher than for conventional HPLC or GC-MS, it lags behind automated immunoassays. Techniques which improve throughput include direct sample injection, LC-multiplexing and sample multiplexing.
Overall, the future of LC-MS/MS is bright as technology is continued to improve, automate, and simplify. While LC-MS/MS is already a mainstay in several areas of the clinical lab, new applications in metabolomics and metallomics are being investigated.
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