The US FDA has cleared the Siemens Healthcare Diagnostics Vitamin D Total Assay for use on the ADVIA Centaur/XP Immunoassay Systems, enabling laboratories to consolidate vitamin D testing with routine testing on a single, fully automated immunoassay platform. The assay, which is traceable to LC/MS/MS (liquid chromatography-mass spectrometry), measures the total level of 25-hydroxyvitamin D [25(OH)D] in serum and plasma to aid in the assessment of vitamin D sufficiency. Measurement of [25(OH)D], the most widely used indicator of vitamin D status, ensures accurate evaluation of patients for deficiency, sufficiency, or toxicity.

As people limit their sun exposure due to the risk of skin cancer, vitamin D deficiency rates have been increasing globally. In the US, approximately 77 per cent of adults are either insufficient or deficient in vitamin D, according to the National Health and Nutrition Examination Survey (NHANES) III from 2001 to 2004. While vitamin D deficiency has long been associated with rickets, osteomalacia (softening of the bones), and osteoporosis, recent studies have also linked it to disease states, including cancer, cardiovascular, diabetes, and autoimmune diseases.

Rising deficiency rates and increasing evidence of vitamin D sufficiency as a general health indicator have driven demand for more vitamin D testing. However, not all vitamin D tests are the same. A number of studies have reported discrepancies between assays used to measure vitamin D, calling into question the ability of some assays to accurately identify individuals affected by vitamin D deficiency.

To ensure accuracy, the Siemens' ADVIA Centaur Vitamin D Total assay measures a patient's total 25(OH) vitamin D level – ~100% of 25 (OH) vitamin D2 and D3, metabolites of the two major forms of vitamin D.  Because circulating 25(OH)D can arise from hydroxylation of either vitamin D2 or D3, measurement of total 25(OH)D (both D2 and D3) is essential for accurate assessment of vitamin D status.

"In order to meet the demand for vitamin D testing, laboratories are under increasing pressure to enhance efficiency while providing reliable results," said David Hickey, CEO, Chemistry, Immunoassay, Automation & Diagnostics IT Business Unit, Siemens Healthcare Diagnostics. "With the ADVIA Centaur Vitamin D Total assay, laboratories can now consolidate vitamin D testing into their existing workflow, saving time and money, while meeting clinicians' expectations for fast and accurate results.  

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