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Huge variation in Vitamin D test results between 4 testers for 8 people – 2013

Four automated 25-OH total vitamin D immunoassays and commercial liquid chromatography tandem-mass spectrometry in Finnish population

Comparative Study Clin Lab . 2013;59(3-4):397-405. doi: 10.7754/clin.lab.2012.120527.
Marja-Kaisa Koivula 1, Nina Matinlassi, Päivi Laitinen, Juha Risteli

Worst case differences for 8 Finns

  • In adddition, there are differences between tests made on the same brand of tester and even the identical tester
  • VitaminDWiki concluded years ago that +- 5 nanograms difference in test results had no significance.
  • Sometimes there can be a 40 nanogram difference between testers for the same blood sample

Tests for Vitamin D contains the following overview/opinion

Vitamin D measurements vary with the same sample of blood – March 2014 has the following
Is the true value 48 nmol -1090 tests @ /is.gd/vitd1090

 Download the PDF from VitaminDWiki

Background: Comparing four fully automated 25-OH-D immunoassays to a commercially available liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with human serum samples from Finnish population.

Methods: 400 samples were analyzed with the Liaison Total Vitamin D, the IDS-iSYS 25-Hydroxy Vitamin D, the ARCHITECT 25-OH Vitamin D, the ADVIA Centaur Vitamin D Total, and a commercially available LC-MS/MS 25-OH D (PerkinElmer) method.

Results: The Liaison method mean value (95% confidence intervals) was 65.6 nmol/L (62.6 - 68.6); the IDS-iSYS mean was 70.3 nmol/L (67.4 - 73.1); the ARCHITECT mean was 69.0 nmol/L (65.5 - 72.5); ADVIA Centaur mean was 71.6 nmol/L (68.9 - 74.3), and the LC-MS/MS mean was 82.8 nmol/L (79.4 - 86.2). The regression coefficients (r) between the LC-MS/MS and immunoassays were 0.650 for Liaison, 0.757 for IDS-iSYS, 0.721 for ARCHITECT and 0.684 for ADVIA Centaur. With the Passing-Bablok analysis, none of the immunoassays gave results equivalent to LC-MS/MS. Two of the four automated 25-OH-vitamin D assays (IDS-iSYS, ADVIA Centaur) were overall in good clinical agreement with LC-MS/MS, even though the results obtained with all compared methods were not equivalent.

Conclusions: In conclusion, in routine clinical laboratory both immunoassays and LC-MS/MS are useful for measuring 25-OH-vitamin D provided that these methods are correctly standardized and especially sample pretreatment is carefully performed.

Created by admin. Last Modification: Tuesday March 2, 2021 01:26:31 GMT-0000 by admin. (Version 10)

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15151 8 samples.jpg admin 02 Mar, 2021 00:57 54.79 Kb 194
15150 Finnish tests.pdf admin 02 Mar, 2021 00:56 327.58 Kb 273