MAY 28, 2014 03:00 PM PDT

Vitamin D Testing in the Clinical Laboratory: The Status in 2014

  • Professor of Endocrine Bone Research Laboratory, Univ of South Australia
      Professor Howard Morris is Professor of Medical Sciences at the University of South Australia and a Chief Medical Scientist in Chemical Pathology at SA Pathology, Adelaide, South Australia. He is currently Vice-President of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) and Chair of the IFCC-International Osteoporosis Foundation Working Group on Standardization of Bone Marker Assays. He has over 30 years experience in Clinical Biochemistry largely managing the Endocrinology laboratory of a large public pathology service. Between 2003 and 2009 he was the Director of the Hanson Institute in Adelaide, the major medical research institute in South Australia. His research investigates the pathophysiology of osteoporosis and the effects of hormones including vitamin D and dietary calcium. He was the Louis Avioli Memorial Lecturer at the 2009 Annual Scientific Meeting of the American Society for Bone and Mineral Research. He is also Chair of the South Australian Department of Health Working Party on Osteoporosis and Fracture Prevention.


    Interest in vitamin D status remains high amongst the public and medical profession alike stimulating a surge in requests for clinical laboratories to measure patient serum 25-hydroxyvitamin D levels. It is stimulated by reports that a low vitamin D status is common and is associated with an increased incidence of a variety of diseases. Questions facing the clinical laboratory providing this service include: How reliable are the various serum 25-hydroxyvitamin D assays that are available to the clinical laboratory and which patient groups benefit most from this test? In the past confidence in the quality of serum 25-hydroxyvitamin D assays has been questioned. An internationally accepted reference measurement procedure and reference standards for serum 25-hydroxyvitamin D assays are now available. Restandardization of routine automated assays has been implemented for a number of assays demonstrating considerable improvement in the accuracy of these assays for most patient groups. However recent data suggest that for some patient groups inaccuracy is still a significant clinical problem. The highest levels of evidence indicate that the elderly with a low vitamin D status benefit from vitamin D and dietary calcium supplementation to reduce risks of premature mortality, falls and fractures. There is no agreement that screening for vitamin D deficiency in the general population is cost effective. However there is agreement that a variety of patients groups can benefit by correcting their vitamin D deficiency. Interpretation of serum 25-hydroxyvitamin D levels remains highly controversial although considerable advances have been made elucidating the physiology of vitamin D metabolite homeostasis.

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