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See detailStandardization of DiaSorin and Roche automated third generation PTH assays with an international standard: impact on clinical populations
CAVALIER, Etienne ULg; DELANAYE, Pierre ULg; LUKAS, Pierre ULg et al

in Clinical Chemistry & Laboratory Medicine (2014), 52(8), 1137-41

Background: Standardization of parathyroid hormone (PTH) assays is a major issue, especially in hemodialyzed (HD) patients. Two automated third generation PTH assays (Roche Elecsys and DiaSorin Liaison ... [more ▼]

Background: Standardization of parathyroid hormone (PTH) assays is a major issue, especially in hemodialyzed (HD) patients. Two automated third generation PTH assays (Roche Elecsys and DiaSorin Liaison) are now available. These assays are specific for the (1-84) PTH and do not cross-react with the (7-84) fragment, contrary to second generation (intact) assays. We aimed to calibrate the two methods against the WHO International PTH Standard (IS) 95/646 to see if the two assays could provide comparable results in a population of healthy subjects, HD patients and patients suffering from primary hyperparathyroidism (PHP). Methods: We selected 79 healthy subjects and two populations of patients presenting PTH disorders: 56 HD and 27 PHP patients. We reconstituted the IS in a pool of human serum containing undetectable levels of 1-84 PTH and prepared 13 serum standards ranging from 0 to 2000 pg/mL. The standards were run on the two instruments to calibrate the assays on the IS. The different populations were run before and after restandardization. Results: As these kits were differently calibrated, the results obtained after restandarization were significantly different. Restandardization process improved concordance between assays and, taking the analytical variability of the two kits into account, the results could be considered to be similar. Conclusions: Restandardization of automated third generation PTH assays with the WHO 1-84 PTH Standard significantly reduces inter-method variability. Reference ranges and raw values are totally transposable from one method to the other in healthy subjects, but also in diseased patients, e.g., with HD or those suffering from PHP. [less ▲]

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See detailPlatelet-rich plasma to treat patellar tendinopathies: a 1 year follow-up.
Kaux, Jean-François ULg; Croisier, Jean-Louis ULg; Bruyère, Olivier ULg et al

in Clinical Chemistry & Laboratory Medicine (2014, June), 52(Special Suppl), 1285

Background: Jumper’s knee is a frequent chronic overuse syndrome of the upper part of the patellar tendon. Platelets contain lots of growth factors which could enhance the healing process of tendons ... [more ▼]

Background: Jumper’s knee is a frequent chronic overuse syndrome of the upper part of the patellar tendon. Platelets contain lots of growth factors which could enhance the healing process of tendons. Infiltration of Platelet Rich Plasma (PRP) may be considered as a recent therapeutic option for chronic tendinopathies. The aim of the current study is to evaluate the clinical status and the return to sports activities in patients with chronic upper patellar tendinopathies up to 1 year after 1 infiltration of PRP. Methods: Twenty patients with chronic upper patellar tendinopathy were enrolled. Assessments were made before infiltration of PRP, and 6 weeks and 3 months and 1 year after the infiltration, using a 10-point Visual Analogic Scale and algofunctional scores (IKDC and VISA-P). Moreover, they had to answer an information questionnaire concerning their life and sports activities. The PRP was obtained with an apheresis system (COM.TEC, Fresenius). Six millilitres of PRP were injected without local anaesthetic. One week after infiltration, patients started a standardised sub-maximal eccentric reeducation. Results: Pain during daily activities significantly decreased with time. VAS has significantly dropped, IKDC and VISA-P significantly improved over the follow-up of 1 year. Seventy percents of patients reported a favourable evolution with decrease of pain, 15% did never report any improvement and 15% were treated surgically. Seventy percents returned to sports activities, 64,3% without any pain, and 50% of them recovered the same sport level. Younger patients seemed to be more susceptible to have an improvement of pain by the PRP infiltration. Conclusions: This study demonstrates that a local infiltration of PRP associated with a submaximal eccentric protocol can improve, at 1 year, symptoms of chronic jumper’s knee in patients non-responsive to classical conservative treatments. [less ▲]

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See detailEvaluation of troponin T on AQT90 Flex and COBAS 8000 as a rule in/out tool in an emergency ward
LE GOFF, Caroline ULg; EVRARD, Séverine ULg; BREVERS, Eric ULg et al

in Clinical Chemistry & Laboratory Medicine (2014, June), 52(Special Suppl), 510

BACKGROUND: Troponin measurement is the gold standard for diagnosis of Acute Myocardial Infarction (AMI). Troponin (highly sensitive (hs), T or I) is measured by immunochemistry instrument or by Point of ... [more ▼]

BACKGROUND: Troponin measurement is the gold standard for diagnosis of Acute Myocardial Infarction (AMI). Troponin (highly sensitive (hs), T or I) is measured by immunochemistry instrument or by Point of Care (POCT). POCT can be useful in emergency lab or ward for a faster diagnosis of patients with chest pain. Our study compared analytical performance of a POCT AQT90 Flex (Radiometer Medical) (AQT) and TnThs Cobas 8000 (Roche Diagnostics) (Cobas). We also compared the clinical performance of both methods at recommended cut-off (14 ng/L for Cobas and 30 ng/ L for AQT). METHODS: We selected 104 patients (296 samples) (range: 6-13822 ng/L) admitted in the Emergency ward for which at least 1 troponin determination (Cobas 8000) had been re-quested in the past 24 hours according to rule in/out procedure applied by this ward. Samples were then measured with the AQT. Inter-assay CV was maximum 8.6% and 9.6% for Cobas and AQT respectively. The cut-off defined as the 99th percentile for Roche was 14 ng/L and the recommended decision threshold value was 30 ng/L for Radiometer. Retrospective analysis of final diagnostic was obtained for all participants: we considered as “true positive” patients for whom a final diagnostic was ST segment-Elevation Myocardial Infarction (STEMI) or non STEMI (NSTEMI). RESULTS: On the whole range of measure, the 2 methods showed a good correlation (r2=0.98). Regression equation was Cobas = 0.98 AQT + 31 ng/L (95%CI of the intercept: (26.7;37.7) and 95% CI of the slope (0.96;1)). When we stratified, for the values <54 ng/L, the equation became Cobas = 0.52 AQT +1.1 ng/L (95%CI of the intercept: (-4.8;5.5) and 95% CI of the slope (0.39;0.69)). Bland and Altman plot did not show any bias. At admission [2-7 hours], 78 (81%) of admitted patients were finally considered as AMI, sensitivity was 92 % [96%] for Cobas and 78% [91%] for AQT. Specificity was 15% for Cobas (cut-off 14ng/L) or 73% (cut-off 54 ng/L) and 76% for AQT. CONCLUSIONS: Overall, there was a good correlation between the 2 methods. However, using a cut-off of 14 ng/L for Cobas is questionable for a rule in/out procedure in an emergency ward. Using 54 ng/L for Roche and 30 ng/L for AQT would have led to the best discrimination between patients presenting AMI or not. [less ▲]

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See detailURINARY AND SALIVARY CORTISOL IN LIQUID CHROMATOGRAPHY–TANDEM MASS SPECTROMETRY: METHOD VALIDATION AND EXPECTED VALUES DETERMINATION
LE GOFF, Caroline ULg; DELCOUR, Sandra ULg; PEETERS, Stéphanie ULg et al

in Clinical Chemistry & Laboratory Medicine (2014, June), 52(Special Suppl), 1241

BACKGROUND: Cortisol measurement is useful in evaluation of Cushing syndrome, adrenal insufficiency, mineralocorticoid excess and congenital adrenal hyperplasia. We developed a liquid ... [more ▼]

BACKGROUND: Cortisol measurement is useful in evaluation of Cushing syndrome, adrenal insufficiency, mineralocorticoid excess and congenital adrenal hyperplasia. We developed a liquid chromatography–tandem mass spectrometry (LCMS/MS) method for salivary and urinary cortisol and we determined the 95th percentile (p95) for the urinary and salivary cortisol. We compared them to the Mayo Clinic expected values. METHODS: Saliva at 8 am and 11 pm and 24h urine were obtained from 32 healthy (22 female, 34.3±9.3 yo) volunteers. We performed validation with the enoval software (Arlenda, Belgium). For the validation, we used water or urine with spiked known amounts of cortisol for the CORS and CTU respectively. For the CORS, samples were centrifuged, deuterium labelled cortisol was added as internal standard and the protein precipated by acetonitril. The supernatant was evaporated, dissolved in methanol acidified with acetic acid and analyzed by LCMS/MS. For CTU, samples were centrifuged, deuterium labelled cortisol was added as internal standard and diluted by the ammonium acetate and analyzed by LCMS/MS. At the Mayo Clinic, the expected values were 1-7.5 μg/L (7 a.m-9 a.m) and <1 μg/L (11-12 p.m) for CORS and 3.5-45 μg/24h (<18yo) for CTU. RESULTS: For the CTU, the with-in run did not exceed 3% (0.4-3%) and the between-run did not exceed 3.1% (0.4-3.1%) for 1.5-750 μg/L. The limit of quantification was 1.5 μg/L. The linearity was good between 1.5 and 750 μg/L. The recovery is 97.9±2.2% (95%CI for the mean: 92.4-101.1%). For the CORS, the with-in run and between run did not exceed 8% (1.9-8%) for 1.15-8.65 μg/L. The limit of quantification was 1.15 μg/L. The analyse presents a good linearity between 1.15 and 8.65 μg/L. The recovery is 99.9±2.9% (95%CI for the mean: 94.2-108.7%). The p95 for the CTU according to the CLSI C28-A3 was 33 μg/24h, and for the CORS was 5.42 μg/L at 8 am and 0.7 μg/L at 12 pm. CONCLUSIONS: Our developed method in liquid chromatography tandem mass spectrometry was validated for the measurement of urinary and salivary cortisol. Our findings indicate that the proposed analytical methods were suitable for routine purposes and useful in many pathological conditions.The expected values confirm these defined by the Mayo Clinic. [less ▲]

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See detailSUITABILITY OF 24,25(OH)2 VITAMIN D3 DETERMINATION WITH AN ADAPTED VERSION OF THE CHROMSYSTEMS® MASSCHROM® 25-OH-VITAMIN D3/D2– LC-MS/MS KIT
SCHLECK, Marie-Louise ULg; NETCHACOVITCH, Matthieu ULg; CRINE, Yannick ULg et al

in Clinical Chemistry & Laboratory Medicine (2014, June), 52(Special Suppl), 1235

BACKGROUND: The enzym CYP24A1 catalyses the conversion of 25(OH)D3 in 24,25(OH)2D3. Recently, loss-of-function mutation of CYP24A1 has been identified in idiopathic infantile hypercalcemia (IIH). This ... [more ▼]

BACKGROUND: The enzym CYP24A1 catalyses the conversion of 25(OH)D3 in 24,25(OH)2D3. Recently, loss-of-function mutation of CYP24A1 has been identified in idiopathic infantile hypercalcemia (IIH). This genetic defect can be highlighted by high 1,25(OH)2D3 and undetectable 24,25(OH)2D3 levels. 24,25(OH)2D3 is also known to interfere with 25(OH)D3 determinations with immunoassays, leading to an overestimation of the 25(OH)D3 concentrations. We adapted the MassChrom kit on the AB SCIEX TQ 5500 in order to systematically provide, next to 25(OH)D3, 25(OH)D2 and C3 epimer, the concentrations of 24,25(OH)2D3. The aim of this study was to evaluate the performance of 24,25(OH)2D3 determination with this modified method. We also wanted to establish the reference value of 24,25(OH)2D3. METHODS: We modified the Chromsystems MassChrom method by adding the 24,25(OH)D3 correspondent transitions and performed a calibration by spiking known amounts of 24.25(OH)2D3. The LOQ was determined with 10 concentration levels of 24,25(OH)2D3. We selected 92 healthy children (40 girls; 2.4±1.51 years) presenting normal calcium levels (2.49±0.13mmol/l) to determine the 95th percentile (p95). RESULTS: The 24,25(OH)2D3 LOQ was 4.7 ng/ml. 85.9% of our subjects were below this LOQ. The p 95 for the 24,25(OH)2D3, according to the CLSI C28-A3, was <6.2 ng/ml. The average serum concentrations (mean±SD) of 25(OH)D3 and 3-epi-25(OH)D3 were 24.48±10.22ng/ml and 2.07±1.86 ng/ml respectively. The 24,25(OH)2D3 levels (r2=0.64) correlated with the 25(OH)D3 levels. CONCLUSIONS: Our adapted method from Chromsystems Vitamin D determination is available to quantify 24,25(OH)2D3. In this context, this method is able to determine high levels of 24,25(OH)2D3 that can possibly cross react with immunoassays. However, as the LOQ was not low enough, we couldn’t establish correct reference value for 24,25(OH)2D3. A derivatization step in the sample preparation would be interesting to improve the sensibility of the method. [less ▲]

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See detailIDS iSYS automated intact procollagen-1-Nterminus pro-peptide assay: method evaluation and reference intervals in adults and children
Morovat, Alireza; Catchpole, Anthony; MEURISSE, Angélique ULg et al

in Clinical Chemistry & Laboratory Medicine (2013), 51(10), 2009-2018

Background: We carried out a technical evaluation of the Immunodiagnostic Systems (IDS) automated intact procollagen- I N-terminus propeptide (PINP) assay on the iSYS platform, and established reference ... [more ▼]

Background: We carried out a technical evaluation of the Immunodiagnostic Systems (IDS) automated intact procollagen- I N-terminus propeptide (PINP) assay on the iSYS platform, and established reference intervals for PINP in both adults and children. Methods: Assay imprecision, recovery and interference were studied. Serum and plasma values were compared, and PINP stability was assessed. Using 828 specimens, IDS iSYS intact PINP and Roche E170 total PINP values were compared. Specimens from 597 adults and 485 children and adolescents were used to establish reference intervals for intact PINP. Results: The method demonstrated good recovery and acceptable imprecision. The assay was unaffected by icterus and lipaemia, but haemolysis decreased measured PINP. Serum and plasma values were comparable. There was a non-linear relation between IDS intact and Roche total PINP values. Pre- and post-menopausal women had comparable PINP values, but there was a difference between women of different age groups. Serum PINP in men showed a decline in young age up to 45 years, but remained steady thereafter. Separate reference intervals were established for four age groups in women and for two age groups in men. Data for children were partitioned into four-year age groups, and these showed PINP to be high with no major gender differences until 12 years of age. Thereafter, values in females decreased in 13–16 years age groups and further in 17–20 years age groups, whereas PINP increased in boys of 13–16 years of age with a subsequent decline at 17–20 years. Conclusions: The IDS iSYS PINP intact assay appears to be reliable. We have established gender- and age-related reference intervals for children and adults based on a relatively large healthy North European population. [less ▲]

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See detailTechnical 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 ULg; ROUSSELLE, Olivier ULg; FERRANTE, Nunzio ULg et al

in Clinical Chemistry & Laboratory Medicine (2013), 51(10), 1983-1989

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 ® 5-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 ▲]

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See detailStaging chronic kidney disease and estimating glomerular filtration rate: an opinion paper about the new international recommendations
DELANAYE, Pierre ULg; CAVALIER, Etienne ULg

in Clinical Chemistry & Laboratory Medicine (2013), 51(10), 1911-1917

Abstract: In January 2013, the international recommendations <br />of the KDIGO (for “ Kidney Disease: Improving <br />Global Outcomes ” ) to define chronic kidney disease <br />(CKD) and classify ... [more ▼]

Abstract: In January 2013, the international recommendations <br />of the KDIGO (for “ Kidney Disease: Improving <br />Global Outcomes ” ) to define chronic kidney disease <br />(CKD) and classify patients in CKD stages have been published. <br />In this opinion article, we will review and discuss <br />the most important guidelines proposed about CKD staging <br />and glomerular filtration rate (GFR) estimating. In <br />particular, we question the choice of fixed knot values <br />at 60 mL/min/1.73 m ² to define CKD. We also question <br />the strategies proposed to measure and use cystatin C <br />results. [less ▲]

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See detailThe diagnostic utility of folate receptor autoantibodies in blood
Sequeira, JM; RAMAEKERS, Vincent ULg; Quadros, EV

in Clinical Chemistry & Laboratory Medicine (2013), 51(3), 545-54

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See detailClinical recognition and aspects of the cerebral folate deficiency syndromes
RAMAEKERS, Vincent ULg; Sequeira, JM; Quadros, EV

in Clinical Chemistry & Laboratory Medicine (2013), 51(3), 497-511

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See detailEvaluation of the cross-reactivity of 25-hydroxyvitamin D2 on seven commercial immunoassays on native samples
LE GOFF, Caroline ULg; PEETERS, Stéphanie ULg; CRINE, Yannick ULg et al

in Clinical Chemistry & Laboratory Medicine (2012), 50(11), 2031-2

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See detailAberrant results observed with four immuno-assays for total and free prostate-specific antigen (PSA) determination: a case-report
CAVALIER, Etienne ULg

in Clinical Chemistry & Laboratory Medicine (2012), 50(3), 583-584

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See detailFatty acids and cardiovascular risk
LE GOFF, Caroline ULg; Leroy, Ludovic; Kaux, Jean-François ULg et al

in Clinical Chemistry & Laboratory Medicine (2011, May), 49(Special Suppl), 313

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See detailElevation of cardiac and oxidative stress biomarkers after a running activity in sedentary subjects
LE GOFF, Caroline ULg; Bury, Thierry ULg; Rodriguez de la Cruz, Carlos ULg et al

in Clinical Chemistry & Laboratory Medicine (2011, May), 49(Special Suppl), 313

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See detailVitamin D: clinical relevance, analytical issues
CAVALIER, Etienne ULg

in Clinical Chemistry & Laboratory Medicine (2011, May), 49(s1), 66

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See detailCystatin C is a reliable marker for estimation of glomerular filtration rate in renal transplantation: validation of a new turbidimetric assay using monospecific sheep antibodies
Bargnoux, A. S.; Cavalier, Etienne ULg; Cristol, J. P. et al

in Clinical Chemistry & Laboratory Medicine (2011), 49(2), 265-70

Background: The potential use of Cystatin C was recently assessed in kidney transplantation. A new particle-enhanced turbidimetric immunoassay (PETIA) that uses sheep antibodies (Binding Site Human ... [more ▼]

Background: The potential use of Cystatin C was recently assessed in kidney transplantation. A new particle-enhanced turbidimetric immunoassay (PETIA) that uses sheep antibodies (Binding Site Human Cystatin C immunoassay) has been developed. Analytical performance of this new assay was evaluated. Clinical relevance was determined by comparison with a reference method in a cohort of kidney transplant patients. Patients and methods: First, the analytical performance of the Binding Site cystatin C kit was tested on SPAPLUS® and Hitachi® analyzers. Second, a comparison study was performed using SPAPLUS® analyzer against two other cystatin C methods (the Siemens-PENIA method on BNII® and the Dako-PETIA application on Olympus AU640®). Third, the glomerular filtration rate (GFR) was estimated using several predictive cystatin C- and creatinine-based equations and compared to GFR measured by an isotopic method (99mTc-DTPA). These predictive algorithms were analyzed with respect to bias, precision and accuracy. Results: Total intra-assay and inter-assay coefficients of variation were below 5%. Values obtained with the SPAPLUS® correlated with the Siemens-PENIA and the Dako-PETIA methods. The creatinine and cystatin C-based equation allowed reliable assessment of GFR in our population of renal transplantation. Conclusions: The use of algorithms based on cystatin C and creatinine could provide a reliable estimate of GFR in kidney transplantation. [less ▲]

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See detailValidation of the Abbott Architect 25(OH)-vitamin D assay
CAVALIER, Etienne ULg; CARLISI, Ignazia ULg; BEKAERT, Anne-Catherine ULg et al

in Clinical Chemistry & Laboratory Medicine (2011), 49(s1), 418

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See detailAnalytical validation of the Liaison Calcitonin_II-Gen (DiaSorin)
Cavalier, Etienne ULg; Carlisi, Ignazia ULg; Bekaert, Anne-Catherine ULg et al

in Clinical Chemistry & Laboratory Medicine (2011), 49(2), 271-275

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