LC-MS/MS for the Clinical Lab
Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has seen "enormous growth" in clinical labs during the last 10-15 years, according to a February 2011 article in Clinical Biochemist Reviews. The authors say LC-MS/MS's analytical specificity is superior to that of immunoassays and conventional high-performance pressure liquid chromatography (HPLC) for low-molecular-weight analytes and has higher throughput than gas chromatography-mass spectrometry (GC-MS).
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Efficacy of Prescribed Vitamin D: 25-OH D2 vs. 25-OH D3
The human body doesn’t produce 25-OH D2 in response to sun exposure. It is made by irradiating fungus and plant matter. When you take 25-OH D2 supplements, a number of metabolic forms of 25-OH D2 are found in the body. Some studies have shown 25-OH D3 (produced by the skin) is more potent, meaning it is more effective at raising Vitamin D blood levels than 25-OH D2. Other studies have shown that both Vitamin D forms are equal. Just recently, a meta-analysis study led by Professor Dr. Goran Bjelakovic addressed the question of which Vitamin D form has better health outcomes and mortality rates.
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Why Healthcare Workers Must Be Vigilant To Test, Catch and Treat Vitamin D Deficiency
Vitamin D testing has exploded on to the scene. With no national guidelines on replacement, and toxicity from supplementation rare, what really counts is not the vitamin D dose but the serum level achieved. For replenishment, follow up testing may be required every three months to ascertain effectiveness of dosing. To learn more about replenishment dosing, maintenance dosing and the testing required for each.
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Testing for vitamin D deficiency or toxicity has become an extremely popular request in the last few years. Along with this popularity, a concern for the accuracy of available tests has also increased. The two most relevant forms of testing are for vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Studies have shown however, that vitamin D assays, in particular competitive binding assays, may be biased to measuring one or the other of these two entities.
Dr. Luzzi is Associate Director of Chemistry in the Department of Pathology & Laboratory Medicine at Henry Ford Hospital, and Adjunct Professor of Pathology at Wayne State University, in Detroit, Michigan, compares and contrasts the different methodologies and discusses the consequences of using an inaccurate assay in the following paper.
>> read more/download article CDC Vitamin D Study
Here's a brief the Control Freaks think might interest you. It was just released by the Institute of Medicine, and it discusses new dietary intakes for calcium and vitamin D. The brief defined four categories of vitamin D status based on serum 25-hydroxyvitamin D and the risk of deficiency, the risk of inadequacy, the sufficiency of dosage and whether or not there may be reason for concern. It presents the most recent national data on vitamin D status in the U.S. population based on these IOM categories. Results are presented by age, sex, race and ethnicity, and, for women, by pregnancy and lactation status.
>> read more/download article HPLC Method for 25-Hydroxyvitamin D Measurement: Comparison with Contemporary Assays
This paper was written in response to the inconsistency and restrictions of commercial assays that measure 25-Hydroxyvitamin D (25-OH D), and the clinical concern that an individual may have received a false diagnosis of low or normal vitamin D depending on which analytical method was utilized. The authors describe a selective validated HPLC method for measurement of both 25-OH D2 and 25-OH-D3, then go on to compare their HPLC method to LC-MS/MS and other commercially available competitive protein-binding assays.
>> read more/download article Does Vitamin D Testing Add Value to Patient Care?
Dr. Ravinder Singh of the Mayo Clinic describes the marked increase in testing for 25-OH-D in clinical labs and poses questions about test performance, method variability, cost effectiveness, and value to patient care.
>> read more/download article Researchers Establish Link Between Obesity, Vitamin D Levels
It is generally understood that obesity is pretty bad for your health. But now researchers are beginning to understand why specifically, obesity is linked to diseases such as cancer, heart disease and diabetes. If you're obese, you likely have reduced levels of vitamin D, which influences cell growth, neuromuscular and immune function and inflammation reduction.
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