Clinical Chemistry AACC Online Job Center
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Clinical Chemistry 53: 1706-1713, 2007; 10.1373/clinchem.2007.086280
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow 086280.Supplemental Data
Right arrow Submit an electronic Letter to
the Editor about this paper
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Azharuddin, M. K.
Right arrow Articles by Talwar, D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Azharuddin, M. K.
Right arrow Articles by Talwar, D.
Related Collections
Right arrow Clinical Immunology
Right arrow Nutrition
Right arrow Lipids, Lipoproteins, and Cardiovascular Risk Factors
Right arrow Automation and Analytical Techniques
(Clinical Chemistry. 2007;53:1706-1713.)
© 2007 American Association for Clinical Chemistry, Inc.

Nutrition

HPLC Method for Plasma Vitamin K1: Effect of Plasma Triglyceride and Acute-Phase Response on Circulating Concentrations

Mohammed K. Azharuddin1, Denis St. J. O’Reilly1, Andrew Gray2 and Dinesh Talwar1,a

1 Scottish Trace Element and Micronutrient Reference Laboratory, Department of Clinical Biochemistry, Royal Infirmary, Glasgow, United Kingdom.
2 Department of Orthopaedics, Royal Infirmary, Glasgow, United Kingdom.

aAddress correspondence to this author at: Department of Biochemistry, Royal Infirmary, Glasgow G4 OSF, UK. Fax 44-0141-553-1703; e-mail dtalwar{at}gri-biochem.org.uk.

Background: The plasma concentration of vitamin K1 (phylloquinone) is the most reliable index for assessing vitamin K status. Our aim was to analytically validate an HPLC method for quantifying phylloquinone in plasma and to examine the effect of plasma triglyceride concentration on the phylloquinone reference interval. We also examined the effect of acute-phase response on phylloquinone concentration in plasma.

Methods: Phylloquinone was extracted from fasting plasma samples by deproteinization and C18 solid-phase extraction, separated by reversed-phase HPLC, and detected fluorometrically after postcolumn reduction with a platinum catalyst. We synthesized a novel internal calibrator, docosyl naphthoate.

Results: The recovery of phylloquinone was >90%. Between-run imprecision was 8.7%–9.0%, and within-run imprecision was 3.8%–7.0%. The linearity was up to 44.8 nmol/L, limit of detection 0.08 nmol/L, and limit of quantification 0.14 nmol/L. The correlation between plasma phylloquinone and triglyceride concentrations was r = 0.7 in the reference population. The 95% reference interval for the phylloquinone:triglyceride ratio was 0.20 to 2.20 nmol/mmol. Plasma concentrations of C-reactive protein were significantly increased, whereas triglyceride and phylloquinone but not the phylloquinone:triglyceride ratio were transiently decreased >50% after surgery.

Conclusion: Phylloquinone population reference intervals should be expressed as a ratio of the triglyceride concentration. Phylloquinone concentrations in plasma are decreased in acute-phase response and, unless corrected for plasma triglyceride concentration, are unlikely to be a reliable index of vitamin K status.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2007 by the American Association for Clinical Chemistry.