Not surprisingly, in vitro diagnostic manufacturers responded by introducing a number of new immunoassays for measuring 25-hydroxyvitamin D. Such assays offer laboratories a means to automate testing in order to meet the increased demand. Laboratories also have developed their own methods, such as liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), to measure vitamin D.
However, as test results accumulated, clinical laboratory professionals observed that vitamin D assays from different commercial sources and platforms produced inconsistent results from the same patient specimen. In some instances, these differences were large enough to affect whether a patient would be classified as having sufficient or deficient vitamin D levels.
Vitamin D Standardization
Source: AACC Clinical Laboratory News
Image credits: Clinical Laboratory News