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

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 ▲]

Analytical Verification of the IDS-iSYS Intact Amino-terminal Propeptide of Type 1 Procollagen (P1NP)

Poster (2012, July 17)

Analytical Performance of the IDS-iSYS CROSSLAPS (CTX-I) Automated Immunoassay

Poster (2012, July 17)

Evaluation of Sclerostin levels in patients suffering from Chronic Kidney Diseases

Poster (2012, July 17)

Difference between total and intact assays for N-terminal propeptide of type I procollagen in renal impaired patients

in Osteoporosis International (2012, March), 23(Supplement 2), 339

New insights on the stability of the Parathyroid hormone as assayed by an automated 3rd generation PTH assay

in Clinica Chimica Acta (2012), 413(1-2), 353-4

Interpretation of serum PTH concentrations with different kits in dialysis patients according to the KDIGO guidelines: importance of the reference (normal) values

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 ▲]

New insights on the stability of the (1-84) PTH as determined with an automated 3rd generation PTH assay

in Clinical Chemistry (2011, October), 57(S10), 190

Automated Measurement of Total 25OH Vitamin D in the IDS iSYS System

Poster (2011, September 17)

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.

Poster (2011, July 28)