Clinical Chemistry
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Clinical Chemistry 55: 1991-1994, 2009. First published September 10, 2009; 10.1373/clinchem.2009.129833
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
clinchem.2009.129833v1
55/11/1991    most recent
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Google Scholar
Right arrow Articles by Seegmiller, J. C.
Right arrow Articles by Lieske, J. C.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Seegmiller, J. C.
Right arrow Articles by Lieske, J. C.
(Clinical Chemistry. 2009;55:1991-1994.)
© 2009 American Association for Clinical Chemistry, Inc.

Proteomics and Protein Markers

Comparison of Urinary Albumin Quantification by Immunoturbidimetry, Competitive Immunoassay, and Protein-Cleavage Liquid Chromatography–Tandem Mass Spectrometry

Jesse C. Seegmiller1, Denis Sviridov3, Timothy S. Larson1,2, Timothy M. Borland1, Glen L. Hortin3,1 and John C. Lieske1,2,a

1 Department of Laboratory Medicine and Pathology, 2 Department of Internal Medicine, Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN; 3 NIH, Department of Laboratory Medicine, Bethesda, MD.

aAddress correspondence to this author at: Renal Function Laboratory, Mayo Clinic Department of Laboratory Medicine and Pathology, 200 First St SW, Rochester, MN 55905. E-mail Lieske.John{at}mayo.edu.

Background: Increased urinary albumin excretion is a well-documented diagnostic and prognostic biomarker for renal disease. Urinary albumin is typically measured in clinical settings by immunoassay methods. However, neither a reference method nor a urine albumin calibration reference material is currently available.

Methods: We quantified urinary albumin in patient samples by using 3 commercially available reagent systems: DiaSorin SPQTM and Beckman Coulter LX® 20 (immunoturbidimetric), and Siemens Immulite® (competitive immunoassay). Results were compared to values obtained by protein-cleavage liquid chromatography–tandem mass spectrometry (LC-MS/MS).

Results: In general, results from the 3 immunoassays agreed with results from LC-MS/MS. However, the SPQ results showed a negative bias across all ranges of albuminuria [(0–200 mg/L, y = 0.91x – 3.74 (CI 0.86–0.96); > 200 mg/L, y = 0.88x – 40.30 (CI 0.76–1.00)], whereas the LX 20 showed minimal bias in the 0–200 mg/L range [y = 0.97x – 88 (CI 0.92–1.02)] and the Immulite assay showed positive bias in the 0–200 mg/L range [y = 1.15x – 4.38 (CI 1.09–1.20)].

Conclusions: These results showed a reasonable quantification of urinary albumin by representative polyclonal and monoclonal immunoassays compared to an LC-MS/MS assay. In addition, the results do not suggest the presence of nonimmunoreactive albumin in urine. However, differences in analytic performance between assays support the need for a reference calibration material and reference method to standardize clinical laboratory measurements of urinary albumin.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2009 by the American Association for Clinical Chemistry.