Technical and clinical evaluation of the VITROS Immunodiagnostic Products 25-OH Vitamin D Total Assay - comparison with marketed automated immunoassays and a liquid chromatography - tandem mass spectrometry method
CAVALIER, Etienne ; ROUSSELLE, Olivier ; FERRANTE, Nunzio et al
in Clinical Chemistry & Laboratory Medicine (in press)
Background: The study was conducted to evaluate the technical and clinical performance of the VITROS ® Immunodiagnostic Products 25-OH Vitamin D Total Assay, and compare it with the performance of five ... [more ▼]
Background: The study was conducted to evaluate the technical and clinical performance of the VITROS ® Immunodiagnostic Products 25-OH Vitamin D Total Assay, and compare it with the performance of five marketed automated assays and a liquid chromatography/mass spectrometry reference method (LC-MS/MS). Methods: Three hundred patient serum samples were used to compare the correlation of the VITROS ® 25-OH Vitamin D Total Assay with both the other immunoassays and the LC-MS/MS method, using Passing-Bablok regression and Bland-Altman analyses. Concordance of the diagnosis of vitamin D status was calculated to test the agreement between the different assays. In addition, samples containing vitamin D2 were used to test the assay ’ s ability to detect the D2 form of the vitamin. Results and conclusions: These results from the VITROS ® 25-OH Vitamin D Total Assay generally correlated well with those from most of the marketed immunoassays. Cross-reactivity of the D2 form was calculated as being close to 100%. Additionally, we found substantial variability in performance amongst the various assays, which suggests the need for optimisation and recalibration of commercial methods. [less ▲]Detailed reference viewed: 4 (0 ULg)
Supplementation, optimal status, and analytical determination of vitamin D: Where are we standing in 2012?
; CAVALIER, Etienne
in Anti-Cancer Agents in Medicinal Chemistry (in press), 12
There is a growing interest for vitamin D in the medical and scientific community as well as in the public medias as illustrated by a huge number of publications. Most experts claim that vitamin D ... [more ▼]
There is a growing interest for vitamin D in the medical and scientific community as well as in the public medias as illustrated by a huge number of publications. Most experts claim that vitamin D deficiency/insufficiency is widespread with potential important public health consequences. It may seem surprising for many persons that a deficiency in a vitamin may be so frequent in countries where food is so diversified and easily available. In fact, vitamin D is not a vitamin stricto sensu as it is mainly synthesized in the skin under the action of UVB rays, while its food sources are scarce. Furthermore, UVB rays are absent during a marked part of the year at latitudes greater than 35-40°, while pollution and cloud cover reduce the number of UVB reaching the earth, and many factors such as age, skin pigmentation, covering clothes, sun creams reduce the capacity of the skin to synthesize vitamin D3. Vitamin D must be hydroxylated to form 1,25dihydroxyvitamin D (1,25OH2D), the active metabolite. As 1,25OH2D is released into the bloodstream and binds to a receptor present in several distant tissues, it may be considered as a hormone, vitamin D being thus a pre-prohormone. In the present article, we review briefly the metabolism and various effects of vitamin D as well as the vitamin D assays and vitamin D treatments. We define vitamin D deficiency/insufficiency considering [less ▲]Detailed reference viewed: 53 (4 ULg)
Distinctive aspects of laboratory testing to evaluate mineral and bone metabolism in patients with chronic kidney disease
; ; CAVALIER, Etienne
in Joint Bone Spine (2012), 79(suppl 2), 99-103Detailed reference viewed: 11 (0 ULg)
Vitamin D and primary hyperparathyroidism (PHPT)
; ; CAVALIER, Etienne et al
in Annales d'Endocrinologie (2012), 73(3), 165-169
Vitamin D deficiency and primary hyperparathyroidism (PHPT) are two common conditions, especially in postmenopausal women. Vitamin D deficiency is said to be even more frequent in PHPT patients than in ... [more ▼]
Vitamin D deficiency and primary hyperparathyroidism (PHPT) are two common conditions, especially in postmenopausal women. Vitamin D deficiency is said to be even more frequent in PHPT patients than in the general population due to an accelerated conversion of 25-hydroxy vitamin D (25OHD) into calcitriol or 24-hydroxylated compounds. Although several studies have reported worsening of PHPT phenotype (larger tumours, higher parathyroid hormone [PTH] levels, more severe bone disease) when vitamin D deficiency coexists whereas vitamin D supplementation in PHPT patients with a serum calcium level less than 3 mmol/L has been shown to be safe (no increase in serum or urinary calcium) and to decrease serum PTH concentration, many physicians are afraid to give vitamin D to already hypercalcemic PHPT patients. It is possible that, in some patients, a persistent vitamin D deficiency induces, in the long-term, an autonomous secretion of PTH (i.e. tertiary hyperparathyroidism). The mechanism by which this could occur is unclear however. Finally, as many, otherwise normal, subjects with vitamin D insufficiency may have an increased serum PTH level we believe that those with vitamin D insufficiency should be excluded from a reference population for serum PTH levels. By doing that, we found that the upper normal limit for serum PTH was 25–30% lower than in the whole population. [less ▲]Detailed reference viewed: 13 (0 ULg)
When should we measure vitamin D concentration in clinical pratice?
; ; et al
in Scandinavian Journal of Clinical and Laboratory Investigation. Supplementum (2012), 72(suppl 243), 129-135
The many recently published data on vitamin D have raised much interest in the medical community. One of the consequences has been a great increase in the prescription of vitamin D concentration ... [more ▼]
The many recently published data on vitamin D have raised much interest in the medical community. One of the consequences has been a great increase in the prescription of vitamin D concentration measurements in clinical practice. It must be reminded that only the measurement of 25-hydroxyvitamin D (25(OH)D) concentration is indicated to evaluate vitamin D status. Furthermore, since vitamin D insuffi ciency is so common, since treatment is inexpensive and has a large safety margin, and since we already have much data suggesting that besides its classic effects on bone and mineral metabolism, vitamin D may potentially be helpful for the prevention/management of several diseases, perhaps should it be prescribed to everyone without prior testing? In our opinion, there are however groups of patients in whom estimation of vitamin D status is legitimate and may be recommended. This includes patients in whom a “ reasonably ” evidence-based target concentration (i.e., based on randomized clinical trials when possible) should be achieved and/or maintained such as patients with rickets/osteomalacia, osteoporosis, chronic kidney disease and kidney transplant recipients, malabsorption, primary hyperparathyroidism, granulomatous disease, and those receiving treatments potentially inducing bone loss. Other patients in whom vitamin D concentration may be measured are those with symptoms compatible with a severe vitamin D defi ciency or excess persisting without explanation such as those with diffuse pain, or elderly individuals who fall, or those receiving treatments which modify vitamin D metabolism such as some anti-convulsants. Measurement of Vitamin D concentrations should also be part of any exploration of calcium/phosphorus metabolism which includes measurement of serum calcium, phosphate and PTH. [less ▲]Detailed reference viewed: 34 (4 ULg)
Establishment of parathyroid hormone (PTH) reference on 10 different assay kits: impact of the recruitment of the population
CAVALIER, Etienne ;
in Osteoporosis International (2012, March), 23(Supplement 2), 360Detailed reference viewed: 11 (1 ULg)
Interpretation of serum PTH concentrations with different kits in dialysis patients according to the KDIGO guidelines: importance of the reference (normal) values
CAVALIER, Etienne ; DELANAYE, Pierre ; VRANKEN, Laura et al
in Nephrology Dialysis Transplantation (2012), 27
Background. The recommended target range for serum parathyroid hormone (PTH) in dialysis patients has changed from 150 to 300 pg/mL in the KDOQI guidelines to two to nine times the upper normal limit in ... [more ▼]
Background. The recommended target range for serum parathyroid hormone (PTH) in dialysis patients has changed from 150 to 300 pg/mL in the KDOQI guidelines to two to nine times the upper normal limit in the KDIGO ones. Although inclusion/exclusion criteria for the reference population are highly important, they are usually not mentioned in the commercial kits. In this study, we used the same reference population of vitamin D-replete normal subjects to establish reference values for 10 commercial PTH kits. We evaluated whether this may improve the classification of dialysis patients according to the KDIGO compared to the use of reference values proposed by the manufacturers. Methods. We measured serum PTH with 10 different kits in 149 haemodialysis patients, and 240 25-OH-vitamin D-replete (>75 nmol/L) individuals with an estimated glomerular filtration rate >60 mL/min/1.73 m2. Results. For the 10 kits, our upper normal limit was lower than those of the manufacturers. The difference was, however, variable from one kit to another. The two kits that yielded the lowest and the highest absolute concentrations classified differently 84/149 patients (56.4%) according to the KDOQI and 53/149 (36.2%) according to the KDIGO using the manufacturers’ normal value.Using our normal values significantly decreased the discrepancies with 24/149 patients (16.1%) being still classified differently. Taking the measurement uncertainty into consideration, 8% of the patients only remained differently classified by these two kits. Conclusions. Using the same vitamin-D-replete population to establish the reference range for 10 commercial PTH kits significantly improved the classification of haemodialysis patients according to the KDIGO target range. [less ▲]Detailed reference viewed: 48 (5 ULg)
Maintenir la PTH entre 2 et 9 fois la valeur de référence supérieure du Laboratoire: d'accord, mais quelle valeur???
CAVALIER, Etienne ; DELANAYE, Pierre ;
in Néphrologie & Thérapeutique (2011, October), 7(5), 411-44727Detailed reference viewed: 22 (0 ULg)
Establishment of Parathyroid hormone reference range on 10 different assay kits: impact of the recruitment of the population
CAVALIER, Etienne ;
Poster (2011, September 18)Detailed reference viewed: 14 (1 ULg)
Impact of the use of the Manufacturer's published reference range for PTH vs. the reference range established in the Laboratory for the classification of the haemodialyzed patients with the KDIGO Guidelines.
CAVALIER, Etienne ; DELANAYE, Pierre ; Vranken, Laura et al
Poster (2011, July 28)Detailed reference viewed: 23 (0 ULg)
Validation of the Abbott Architect 25(OH)-vitamin D assay
CAVALIER, Etienne ; CARLISI, Ignazia ; BEKAERT, Anne-Catherine et al
in Clinical Chemistry & Laboratory Medicine (2011), 49(s1), 418Detailed reference viewed: 61 (2 ULg)
Cross-reactivity of 25-hydroxy vitamin D2 from different commercial immunoassays for 25-hydroxy vitamin D: an evaluation without spiked samples.
CAVALIER, Etienne ; ; CARLISI, Ignazia et al
in Clinical chemistry and laboratory medicine : CCLM / FESCC (2011), 49(3), 555-8Detailed reference viewed: 32 (1 ULg)
Dosage de la 25-OH vitamine D: attention aux erreurs analytiques!
Cavalier, Etienne ; Carlisi, Ignazia ; Delanaye, Pierre et al
in 27ème Congrès de la Société Française d'Endocrinologie - Deauville, 29 septembre - 2 octobre 2010 (2010, September)Detailed reference viewed: 63 (3 ULg)
Interpretation of serum parathyroid hormone concentrations in dialysis patients: what do the KDIGO guidelines change for the clinical laboratory?
; Cavalier, Etienne ;
in Clinical Chemistry & Laboratory Medicine (2010), 48(6), 769-774Detailed reference viewed: 41 (3 ULg)
Measurement uncertainty of 25-OH vitamin D determination with different commercially available kits: impact on the clinical cut offs
Cavalier, Etienne ; Rozet, Eric ; Gadisseur, Romy et al
in Osteoporosis International (2010), 21Detailed reference viewed: 74 (10 ULg)
Measurement uncertainty for the analysis of serum 25-hydroxyvitamin D: response to Stepman and Thienpont
Cavalier, Etienne ; Delanaye, Pierre ; et al
in Osteoporosis International (2010), 21Detailed reference viewed: 38 (2 ULg)
Les cibles thérapeutiques pour la PTH dans les nouvelles recommandations du KDIGO: la fin d'un cauchemar?
Cavalier, Etienne ; ; Delanaye, Pierre et al
in Néphrologie & Thérapeutique (2010)Detailed reference viewed: 10 (1 ULg)
La vitamine D : effets « classiques », « non classiques » et évaluation du statut du patient
Cavalier, Etienne ;
in Médecine Nucléaire : Imagerie Fonctionnelle et Métabolique (2009), 33Detailed reference viewed: 60 (7 ULg)
Vitamin D: current status and perspectives.
Cavalier, Etienne ; Delanaye, Pierre ; Chapelle, Jean-Paul et al
in Clinical Chemistry & Laboratory Medicine (2009), 47(2), 120-127
Abstract The role of vitamin D in maintaining bone health has been known for decades. Recently, however, the discovery that many tissues expressed the vitamin D receptor and were able to transform the 25 ... [more ▼]
Abstract The role of vitamin D in maintaining bone health has been known for decades. Recently, however, the discovery that many tissues expressed the vitamin D receptor and were able to transform the 25-OH vitamin D into its most active metabolite, 1,25-(OH)(2) vitamin D, has led to a very promising future for this "old" molecule. Indeed, observational studies, and more and more interventional studies, are raising the importance of a significant vitamin D supplementation for not-only skeletal benefits. Among them, 25-OH vitamin D has been found to play an important role in prevention of cancers, auto-immune diseases, cardiovascular diseases, diabetes, and infections. Vitamin D deficiency, defined as serum 25-OH vitamin D levels <30 ng/mL, is very common in our population. The cost/benefit ratio and some recently published studies are clearly now in favor of a controlled and efficient vitamin D supplementation in these patients presenting a 25-OH vitamin D level <30 ng/mL. More attention should also be focused on pregnant and lactating women, as well as children and adolescents. Clin Chem Lab Med 2009;47. [less ▲]Detailed reference viewed: 183 (17 ULg)
Vitamine D: effets « phosphocalciques » et « non-phosphocalciques ».
Cavalier, Etienne ;
Conference (2008, October)Detailed reference viewed: 28 (2 ULg)