INTRODUCTION: Loss of renal function is accompanied by progressive increase in serum levels of intact parathyroid hormone (iPTH) in patients with end-stage renal disease (ESRD). There is a paucity of data regarding levels of PTH-(1-84) and its large carboxyl-terminal fragments (large C-PTH fragments) and progressive loss of kidney function in patients with chronic kidney disease (CKD). The current study was undertaken to describe the glomerular filtration rate (GFR)-dependent plasma concentrations of PTH-(1-84) and related large C-PTH fragments in adult patients with CKD by using different commercially available PTH assays. METHODS: We studied 80 Caucasian patients with CKD stages 1-5 without renal replacement therapy. Creatinine clearance was calculated by the Modification of Diet in Renal Disease (MDRD) formula. Levels of iPTH were determined by second-generation assays (iPTH Elecsys system, Roche Diagnostics; DUO total iPTH, Scantibodies Laboratory, Inc.; iPTH, Nichols Institute Diagnostics). Third-generation assays were used to measure PTH-(1-84) (CAP (cyclase activating PTH), Scantibodies; Bio-Intact PTH, Nichols). Levels of large C-PTH fragments and ratios of PTH-(1-84)/large C-PTH fragments were calculated and statistical analyses performed. RESULTS: Levels of iPTH and PTH-(1-84) showed CKD stage-dependent increases. Variations among the assays increased with progressive loss of kidney function. The assay from Scantibodies showed a GFR-dependent decrease of the ratio 1-84 PTH / large C-PTH fragment that was not observed with the Nichols assay. CONCLUSION: Increasing variations among the assays with progression of CKD emphasize the fact that the interpretation of measurements must take into consideration the specific assay. We found evidence for a possible preferential increase of the level of large C-PTH fragments over 1-84 PTH in a CKD stage-dependent manner (Scantibodies). The clinical implications of this finding have to be further evaluated by bone biopsy studies.
INTRODUCTION: Loss of renal function is accompanied by progressive increase in serum levels of intact parathyroid hormone (iPTH) in patients with end-stage renal disease (ESRD). There is a paucity of data regarding levels of PTH-(1-84) and its large carboxyl-terminal fragments (large C-PTH fragments) and progressive loss of kidney function in patients with chronic kidney disease (CKD). The current study was undertaken to describe the glomerular filtration rate (GFR)-dependent plasma concentrations of PTH-(1-84) and related large C-PTH fragments in adult patients with CKD by using different commercially available PTH assays. METHODS: We studied 80 Caucasian patients with CKD stages 1-5 without renal replacement therapy. Creatinine clearance was calculated by the Modification of Diet in Renal Disease (MDRD) formula. Levels of iPTH were determined by second-generation assays (iPTH Elecsys system, Roche Diagnostics; DUO total iPTH, Scantibodies Laboratory, Inc.; iPTH, Nichols Institute Diagnostics). Third-generation assays were used to measure PTH-(1-84) (CAP (cyclase activating PTH), Scantibodies; Bio-Intact PTH, Nichols). Levels of large C-PTH fragments and ratios of PTH-(1-84)/large C-PTH fragments were calculated and statistical analyses performed. RESULTS: Levels of iPTH and PTH-(1-84) showed CKD stage-dependent increases. Variations among the assays increased with progressive loss of kidney function. The assay from Scantibodies showed a GFR-dependent decrease of the ratio 1-84 PTH / large C-PTH fragment that was not observed with the Nichols assay. CONCLUSION: Increasing variations among the assays with progression of CKD emphasize the fact that the interpretation of measurements must take into consideration the specific assay. We found evidence for a possible preferential increase of the level of large C-PTH fragments over 1-84 PTH in a CKD stage-dependent manner (Scantibodies). The clinical implications of this finding have to be further evaluated by bone biopsy studies.
Authors: Johann Herberth; Adam J Branscum; Hanna Mawad; Tom Cantor; Marie-Claude Monier-Faugere; Hartmut H Malluche Journal: Am J Kidney Dis Date: 2010-03-27 Impact factor: 8.860
Authors: Sanjeev Patel; Jeffrey L Barron; Mehdi Mirzazedeh; Hugh Gallagher; Steve Hyer; Tom Cantor; William D Fraser Journal: J Bone Miner Metab Date: 2010-06-03 Impact factor: 2.626
Authors: Charles J Diskin; Thomas J Stokes; Linda M Dansby; Lautrec Radcliff; Thomas B Carter Journal: Int Urol Nephrol Date: 2010-06-12 Impact factor: 2.370
Authors: J Herberth; M-C Monier-Faugere; H W Mawad; A J Branscum; Z Herberth; G Wang; T Cantor; H H Malluche Journal: Clin Nephrol Date: 2009-07 Impact factor: 0.975