Day to Day blood test variation less than 8 percent
From a slide presented by From Center for Disease Control
Isotope Dilution Tandem Mass Spectrometry Coupled to Liquid Chromatography (LC-MS/MS)
Precision <8% day-to-day variation
See also VitaminDWiki
All items in Vitamin D Test 46 items as of Jan 2012
Vitamin D test results vary as much as 30 ng between test labs – Jan 2012
Vitamin D measurements of individuals vary by 3 ng within 6 days – June 2011
Vitamin D blood testing within plus or minus 7 percent – Mar 2010 variation between labs
Comparison of vitamin D blood tests – worse case off by 15% – Aug 2010 variation between labs
20 % change in vitamin D levels of critically ill during a 24 hour period – Oct 2011 has the following graph
