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Test kit accuracy

If the directions are followed correctly, Heartland Assays reports a 95% confidence interval, which means that 95% of the time, vitamin D serum analysis shows an accurate reflection of the sample provided. To maximize the accuracy of the results, please follow the directions provided with the kit as closely as possible. Make sure your hands are clean before administering the kit and limit contact with other surfaces to prevent contamination.


Please note that hydration status and anemic state have been found to sway blood spot results, so keep this in mind prior to completing your test. We recommend athletes complete their test prior to any major fluid loss or gain.


Heartland Assays recently conducted a study comparing the accuracy of dried blood spot analysis using the LC/MS/MS method, the gold standard of blood spot analysis, to serum analysis for measuring 25(OH)D status. The researchers found that the dried blood spot procedure, when administered according to the directions provided within the test kits, is recorded with 101% accuracy compared to a serum blood draw. The results of this study are expected to be published sometime in 2017.


If you have any questions about the accuracy of our kit, or are interested in reviewing the study that explored the accuracy of the blood spot card analysis, please contact us at info@vitamindcouncil,org, and we can provide you with that analysis once it is released to the public.