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Evaluation of a new immunoassay for cystatin C, based on a double monoclonal principle, in men with normal and impaired renal function

Ristiniemi, Noora; Savage, Caroline; Bruun, Laila LU ; Pettersson, Kim; Lilja, Hans LU and Christensson, Anders LU (2012) In Nephrology Dialysis Transplantation 27(2). p.682-687
Abstract
Elevated cystatin C in blood reflects impaired glomerular filtration rate (GFR), but current cystatin C assays, based on polyclonal antibodies and immunoturbidimetric or nephelometric detection, have several limitations. We evaluated a new immunoassay based on monoclonal antibodies in samples from patients with and without chronic kidney disease (CKD). The study enrolled 170 men without known CKD (Group A) and 104 men with CKD (Group B). All patients were assessed with iohexol clearance, plasma creatinine and plasma cystatin C by a conventional particle-enhanced immunoturbidimetric assay (PETIA) and by the new double monoclonal assay. In Group A, three serial blood draws were performed at median intervals of 4 h and 12 days between... (More)
Elevated cystatin C in blood reflects impaired glomerular filtration rate (GFR), but current cystatin C assays, based on polyclonal antibodies and immunoturbidimetric or nephelometric detection, have several limitations. We evaluated a new immunoassay based on monoclonal antibodies in samples from patients with and without chronic kidney disease (CKD). The study enrolled 170 men without known CKD (Group A) and 104 men with CKD (Group B). All patients were assessed with iohexol clearance, plasma creatinine and plasma cystatin C by a conventional particle-enhanced immunoturbidimetric assay (PETIA) and by the new double monoclonal assay. In Group A, three serial blood draws were performed at median intervals of 4 h and 12 days between samples, to also allow assessments of the variability in cystatin C values with the new assay. Concordance correlation coefficients and the 95% limits of agreement were used to estimate the agreement of reciprocal cystatin C and reciprocal creatinine with iohexol clearance. Median iohexol clearance (mL/min/1.73 m(2)) was 81 [interquartile range (IQR) 70, 92] in Group A and 23 (IQR 16, 34) in Group B. The concordance correlation with GFR for the new cystatin C assay compared to the established assay was similar in Group A (0.441 versus 0.465) but higher in Group B (0.680 versus 0.593). Cystatin C measured by both assays exhibited closer agreement with GFR than creatinine. The agreement between the two cystatin C assays was high, with concordance correlations of 0.815 in Group A and 0.935 in Group B. Compared to the conventional assay, the new assay tended to yield lower values of cystatin C at the low end of the range in Group A. The new cystatin C assay exhibited small intraindividual variability across serial samples (coefficient of variation < 6%). In this first clinical evaluation, the new cystatin C assay performed similarly to the established PETIA in patients with normal GFR and better in patients with CKD. The new assay may offer an alternative to current commercial assays to detect and monitor impaired kidney function. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
creatinine, cystatin C, glomerular filtration rate, iohexol clearance, renal function
in
Nephrology Dialysis Transplantation
volume
27
issue
2
pages
682 - 687
publisher
Oxford University Press
external identifiers
  • wos:000300421300034
  • scopus:84856876292
ISSN
1460-2385
DOI
10.1093/ndt/gfr350
language
English
LU publication?
yes
id
cf0dbffa-4ff4-4d8c-a47e-deff39a80732 (old id 2409543)
date added to LUP
2012-04-02 09:30:03
date last changed
2017-01-01 06:25:19
@article{cf0dbffa-4ff4-4d8c-a47e-deff39a80732,
  abstract     = {Elevated cystatin C in blood reflects impaired glomerular filtration rate (GFR), but current cystatin C assays, based on polyclonal antibodies and immunoturbidimetric or nephelometric detection, have several limitations. We evaluated a new immunoassay based on monoclonal antibodies in samples from patients with and without chronic kidney disease (CKD). The study enrolled 170 men without known CKD (Group A) and 104 men with CKD (Group B). All patients were assessed with iohexol clearance, plasma creatinine and plasma cystatin C by a conventional particle-enhanced immunoturbidimetric assay (PETIA) and by the new double monoclonal assay. In Group A, three serial blood draws were performed at median intervals of 4 h and 12 days between samples, to also allow assessments of the variability in cystatin C values with the new assay. Concordance correlation coefficients and the 95% limits of agreement were used to estimate the agreement of reciprocal cystatin C and reciprocal creatinine with iohexol clearance. Median iohexol clearance (mL/min/1.73 m(2)) was 81 [interquartile range (IQR) 70, 92] in Group A and 23 (IQR 16, 34) in Group B. The concordance correlation with GFR for the new cystatin C assay compared to the established assay was similar in Group A (0.441 versus 0.465) but higher in Group B (0.680 versus 0.593). Cystatin C measured by both assays exhibited closer agreement with GFR than creatinine. The agreement between the two cystatin C assays was high, with concordance correlations of 0.815 in Group A and 0.935 in Group B. Compared to the conventional assay, the new assay tended to yield lower values of cystatin C at the low end of the range in Group A. The new cystatin C assay exhibited small intraindividual variability across serial samples (coefficient of variation &lt; 6%). In this first clinical evaluation, the new cystatin C assay performed similarly to the established PETIA in patients with normal GFR and better in patients with CKD. The new assay may offer an alternative to current commercial assays to detect and monitor impaired kidney function.},
  author       = {Ristiniemi, Noora and Savage, Caroline and Bruun, Laila and Pettersson, Kim and Lilja, Hans and Christensson, Anders},
  issn         = {1460-2385},
  keyword      = {creatinine,cystatin C,glomerular filtration rate,iohexol clearance,renal function},
  language     = {eng},
  number       = {2},
  pages        = {682--687},
  publisher    = {Oxford University Press},
  series       = {Nephrology Dialysis Transplantation},
  title        = {Evaluation of a new immunoassay for cystatin C, based on a double monoclonal principle, in men with normal and impaired renal function},
  url          = {http://dx.doi.org/10.1093/ndt/gfr350},
  volume       = {27},
  year         = {2012},
}