Measurement uncertainty of 25-OH vitamin D determination with different commercially available kits: impact on the clinical cut offs

Cavalier, Étienne; Rozet, Eric; Gadisseur, Romy; Carlisi, Agnès; Monge, Marie; Chapelle, Jean-Paul; Hubert, Philippe; Souberbielle, Jean‐Claude

doi:10.1007/s00198-009-1052-5

Cited by 36 publications

(30 citation statements)

References 19 publications

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“…Although we utilized the DiaSorin radioimmunoassay in determining our values, the reference values above are a reflection of published guidelines based on a variety of assays. Heaney (4-7) has advocated concern for levels ,32 ng/mL based on all available tests at the time those reports were published, but multiple authors caution the reader on the variability of assays (7,12), as well as interlaboratory variation using the same assay (12,33). The ranges for deficiency, insufficiency, and subtherapeutic levels represent our best estimate based on available published guidelines, understanding the inherent limitations in measurement.…”

Section: Description Of the Final Samplementioning

confidence: 99%

“…Difficulties in establishing normal ranges of serum vitamin D are further complicated by variability in the assays utilized (12,33), as well as in precision in the performance of a given assay at a given laboratory. Highperformance liquid chromatography is the gold standard used in the research setting but is expensive and rarely available at many institutions.…”

Section: New Recommendations For Therapeutic Rangesmentioning

confidence: 99%

“…Highperformance liquid chromatography is the gold standard used in the research setting but is expensive and rarely available at many institutions. Radioimmunoassay technology is the best performer commercially available in the USA at reasonable cost, but it too has limitations of accuracy and precision and depends on both the individual laboratory and the individual assay producer (12,33,43). Some of the earlier technologies using chemibioluminescence protein-binding assays gave falsely elevated readings but were widely used until recently (44).…”

Section: New Recommendations For Therapeutic Rangesmentioning

confidence: 99%

“…This presents a challenge in office settings and in many tertiary care centers, where samples are sent to outside laboratories and results are reported without details of assay and methodology employed. Because of assay variability and uncertainty, Cavalier et al (33) recommend ensuring a patient's vitamin D25(OH) level is at least 40 ng/mL if the clinician's goal is a level of 32 ng/mL.…”

Section: New Recommendations For Therapeutic Rangesmentioning

confidence: 99%

“…This investigation is limited first by the relatively small number of subjects and by problems inherent in assays for vitamin D (12,33,44). A second limitation was the premise that patients were at the minimum therapeutic vitamin D levels at the time of their injuries in the acute cohort.…”

Section: Study Limitationsmentioning

confidence: 99%

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Influence of Season, Ethnicity, and Chronicity on Vitamin D Deficiency in Traumatic Spinal Cord Injury

Oleson

Patel

Wuermser

2010

The Journal of Spinal Cord Medicine

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Background: Inadequate levels of vitamin D increase the risk of osteoporosis, a highly prevalent condition in patients with traumatic spinal cord injury (SCI). Reduced sunlight and dark skin further contribute to low vitamin D levels. Objectives: To compare serum 25-hydroxy vitamin D [vitamin D25(OH)] levels in acute and chronic SCI and to explore seasonal and ethnic differences among patients with acute and chronic SCI. Patients/Methods: Patients (N 5 96) aged 19 to 55 years with C3-T10 motor complete SCI participated. Acute SCI was 2 to 6 months after injury, whereas chronic SCI was at least 1 year from injury. Serum vitamin D25(OH), calcium, and parathyroid hormone were drawn during summer or winter months. Vitamin D deficiency (,13 ng/mL), insufficiency (,20 ng/mL), and subtherapeutic (,32 ng/mL) levels were compared for all groups. A 3-way analysis of covariance was adopted to determine significant main effects of season, chronicity, and ethnicity. Interactions between season and chronicity, season and ethnicity, and chronicity and ethnicity were evaluated. Evaluation of a 3-way interaction among season, chronicity, and ethnicity was completed. Results: In summer, 65% of patients with acute SCI and 81% of patients with chronic SCI had subtherapeutic vitamin D levels, whereas in winter, 84% with acute SCI and 96% with chronic SCI had vitamin D25(OH) (,32ng/mL). Lower vitamin D25(OH) levels were observed in African Americans relative to whites. Significant main effects were noted for season (P 5 0.017), chronicity (P 5 0.003), and ethnicity (P , 0.001). However, interactions between 2 or more factors were not found. Conclusions: Vitamin D insufficiency and deficiency are found in the majority of patients with chronic SCI and in many with acute SCI. Initial screening for serum vitamin D25(OH) levels should be performed early in rehabilitation. Periodic monitoring in the chronic setting is highly recommended.

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Section: Description Of the Final Samplementioning

confidence: 99%

Section: New Recommendations For Therapeutic Rangesmentioning

confidence: 99%

Section: New Recommendations For Therapeutic Rangesmentioning

confidence: 99%

Section: New Recommendations For Therapeutic Rangesmentioning

confidence: 99%

Section: Study Limitationsmentioning

confidence: 99%

See 3 more Smart Citations

Influence of Season, Ethnicity, and Chronicity on Vitamin D Deficiency in Traumatic Spinal Cord Injury

Oleson

Patel

Wuermser

2010

The Journal of Spinal Cord Medicine

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Assessing vitamin D status: Pitfalls for the unwary

Lai

Lucas

Clements

et al. 2010

Molecular Nutrition Food Res

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The use of vitamin D testing has grown rapidly in the recent times as a result of increased interest in the role of vitamin D in health. Although the generally accepted measure of vitamin D status is circulating 25(OH)D concentration, there is little consensus on which assay method should be used. Commonly used assays include competitive protein-binding assay, RIA, enzyme immunoassay, chemiluminescence immunoassays, HPLC, and LC-MS/MS, each with its own advantages and disadvantages. However, there is significant interassay and interlaboratory variability in measurements. Our simulation of the published data showed that using a deficiency cut-point of 50 nmol/L, 57% of samples assessed using a chemiluminescence immunoassay were classified as deficient compared with 41% of samples assessed using LC-MS/MS; a 20% misclassification rate. Similar rates of misclassification were seen at 75 nmol/L. This has implications for clinical practice and decision limits for vitamin D supplementation, suggesting that cut-points should be assay specific rather than universal and that greater harmonization between laboratories is required. Newer assays using alternative biological samples to determine the circulating 25(OH)D have been proposed and advances in the genetics of vitamin D and the role of vitamin D-binding protein may improve future assay accuracy.

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Measurement uncertainty for the analysis of serum 25-hydroxyvitamin D: response to Stepman and Thienpont

2009

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Measurement uncertainty of 25-OH vitamin D determination with different commercially available kits: impact on the clinical cut offs

Cited by 36 publications

References 19 publications

Influence of Season, Ethnicity, and Chronicity on Vitamin D Deficiency in Traumatic Spinal Cord Injury

Influence of Season, Ethnicity, and Chronicity on Vitamin D Deficiency in Traumatic Spinal Cord Injury

Assessing vitamin D status: Pitfalls for the unwary

Measurement uncertainty for the analysis of serum 25-hydroxyvitamin D: response to Stepman and Thienpont

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