25-Hydroxyvitamin D, known for its role in bone health and calcium absorption, also appears to affect immune function, neurodegenerative diseases, cardiovascular diseases, metabolic dsorders, and other conditions.  Hence, the importance of maintaining optimal levels of Vitamin D has created considerable demand for an accurate method for assessing vitamin D status, whether it is from serum or dried blood samples (blood spot). Unfortunately several commonly used immunoassays, one of which has been utilized extensively in the past to establish reference ranges, have been found to be inaccurate and associated with high inter-laboratory variability. 


Therefore, Doctor’s Data (DDI) developed very precise and accurate liquid chromatography tandem mass spectrometry (LC-MS/MS) methods for 25-OH vitamin D2 and D3 levels from serum and dried blood spot samples. To further assess the accuracy of this technology, several analyses were performed that compared levels of vitamin D extracted from both serum and dried blood spots.



Doctor’s Data scientific team has developed technological enhancements that overcome the inherent problems associated with the collection and analysis of blood spots.  As seen in Figure 1 above, excellent agreement has been demonstrated between vitamin D results from the DDI’s blood spot method versus serum determinations using LC-MS/MS.   

       Click image for web version of sample report   
This assay performance data provides assurance that clinicians can have full confidence in DDI’s vitamin D results for their patients using both biological matrices, as a source for both a reliable screening tool, and a sensitive indicator of therapeutic intervention.


If you have questions about this or any of our other tests or to order test collection kits, please contact us.  *To help us assist you promptly, please include your full name and/or Doctor's Data account number.  
Want to see the latest research on this topic?

Gernand AD, Simhan HN, Klebanoff MA, Bodnar LM. Maternal serum 25-hydroxyvitamin D and measures of newborn and placental weight in a U.S. multicenter cohort study.  J Clin Endocrinol Metab. 2013 Jan;98(1):398-404.

Michos ED, Martin S, Jones S. 25-Hydroxyvitamin D Levels and Lipoprotein Cholesterol Subfractions: The Very Large Database of Lipids-Vitamin D Study. J Am Coll Cardiol. 2013;61

Durup D, Jørgensen HL, Christensen J, Schwarz P, Heegaard AM, Lind B.  A reverse J-shaped association of all-cause mortality with serum 25-hydroxyvitamin D in general practice: the CopD study.  J Clin Endocrinol Metab. 2012 Aug;97(8):2644-52.

Other Doctor’s Data tests that assess nutritional status:

Why choose Doctor’s Data Inc.?

Doctor’s Data, Inc. (DDI) a premier clinical laboratory with over 40 years’ experience, provides specialty testing to healthcare practitioners around the world.  DDI is a licensed CLIA laboratory
with appropriate state certifications and participates in numerous quality assurance/proficiency testing programs including the College of American Pathology, New York State DOH and Le Centre de Toxicologie du Quebec.