Effect of Method and Collection Medium on Chromogranin A Reference Ranges

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SAT 326-337-Hormone-Dependent Tumors
Bench to Bedside
Saturday, June 15, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SAT-337
Kristin K Clemens*1, Hala H Mosli2, Alan Dennis3, Walter Kocha4, Linda Asher1 and Stan Van Uum1
1Western University, London, ON, Canada, 2King Abdulaziz University Hospital, Jeddah, Saudi Arabia, 3London Laboratory Services Group, London, ON, Canada, 4London Health Sciences Centre, London, ON, Canada
Background: The accurate measurement and interpretation of Chromogranin A (CGA) is of utmost importance for the care of patients with neuroendocrine neoplasias (NEN’s). Information on the reference ranges of several commercially available CGA assays is limited, including the effect of the collection medium. The aims of this study were to determine the reference range of CGA for both plasma and serum, and to compare the serum vs. EDTA plasma CGA levels across assays.

Methods: We collected serum and plasma samples in 61 healthy subjects. All samples were analyzed in a single laboratory using CGA ELISA assays from CisBio (both serum and plasma), Alpco (both serum and plasma), Dako (plasma only), the RIA from CisBio (plasma only) and a new flash chemiluminescent method from Invitron (plasma only). Reference ranges were determined using a bootstrap non-parametric procedure, and Passing-Bablok non-parametric regression. Paired T tests were used to compare results across assays and plasma vs. serum values respectively.

Results: The reference ranges were calculated for CGA values specified by assay and medium. There was considerable variation across assays both for plasma and for serum, with serum ranges often significantly lower then plasma ranges. Further, for several assays, the reference range that we established was significantly different from the reference range provided in package inserts.

Conclusions: Reference ranges for CGA in healthy subjects may considerably differ from package insert references. Reference ranges need to be established separately for serum and plasma. This information is critical for correct decision-making in the care of patients with NEN’s.

Nothing to Disclose: KKC, HHM, AD, WK, LA, SV

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

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