Logo image
Effect of specimen type on free immunoglobulin light chains analysis on the Roche Diagnostics cobas 8000 analyzer
Journal article   Open access   Peer reviewed

Effect of specimen type on free immunoglobulin light chains analysis on the Roche Diagnostics cobas 8000 analyzer

Louis S Nelson, Bryan Steussy, Cory S Morris and Matthew D Krasowski
SpringerPlus, Vol.4(1), pp.1-9
12/2015
DOI: 10.1186/s40064-015-1546-x
PMCID: PMC4671985
PMID: 26682113
url
https://doi.org/10.1186/s40064-015-1546-xView
Published (Version of record) Open Access

Abstract

The measurement of free immunoglobulin light chains is typically performed on serum; however, the use of alternative specimen types has potential benefits. Using the Freelite™ kappa and lambda free light chains assay on a Roche Diagnostics cobas 8000 c502 analyzer, we compared three specimen types (serum, EDTA-plasma and lithium heparin plasma separator gel-plasma) on 100 patients. Using Deming regression and eliminating outliers (limiting data to light chain concentrations below 400 mg/L), the three specimen types showed comparable results for kappa light chain concentration, lambda light chain concentration, and kappa/lambda ratio with slopes close to 1.0 and y-intercepts close to zero. EDTA-plasma showed slightly more positive bias relative to serum than lithium heparin. Analysis using EDTA-plasma and lithium heparin plasma showed comparable linearity, precision, and temperature stability. A single sample showing hook effect (not in the comparison set) gave comparable results using either plasma specimen type. For the Freelite™ kappa and lambda free light chains assay, both EDTA-plasma or lithium heparin-plasma can serve as acceptable substitutes for serum, at least for the Roche cobas 8000 analyzer.
Nephelometry Immunoglobulin light chains Plasma Serum Research Laboratory automation

Details

Metrics

Logo image