Comparison of serum, EDTA plasma and P100 plasma for luminex-based biomarker multiplex assays in patients with chronic obstructive pulmonary disease in the SPIROMICS study

Wanda K O’neal ,Mary Beth Scholand,Bruce E Miller ,Stephanie A Christenson ,Richard E Kanner ,David J Couper ,Patricia V Basta ,Claire M Doerschuk ,Nadia N Hansel ,Meilan K Han ,Fernando J Martínez ,Eric C Kleerup ,Stephen P Peters ,Stephen I Rennard ,Jeffrey L Curtis ,Ruth Tal‐Singer ,R Graham Barr ,Wayne H Anderson ,Elizabeth E Carretta ,Eugene R Bleecker ,Prescott G Woodruff ,Sonia M Davis

doi:10.1186/1479-5876-12-9

Abstract

BackgroundAs a part of the longitudinal Chronic Obstructive Pulmonary Disease (COPD) study, Subpopulations and Intermediate Outcome Measures in COPD study (SPIROMICS), blood samples are being collected from 3200 subjects with the goal of identifying blood biomarkers for sub-phenotyping patients and predicting disease progression. To determine the most reliable sample type for measuring specific blood analytes in the cohort, a pilot study was performed from a subset of 24 subjects comparing serum, Ethylenediaminetetraacetic acid (EDTA) plasma, and EDTA plasma with proteinase inhibitors (P100™).Methods105 analytes, chosen for potential relevance to COPD, arranged in 12 multiplex and one simplex platform (Myriad-RBM) were evaluated in duplicate from the three sample types from 24 subjects. The reliability coefficient and the coefficient of variation (CV) were calculated. The performance of each analyte and mean analyte levels were evaluated across sample types.Results20% of analytes were not consistently detectable in any sample type. Higher reliability and/or smaller CV were determined for 12 analytes in EDTA plasma compared to serum, and for 11 analytes in serum compared to EDTA plasma. While reliability measures were similar for EDTA plasma and P100 plasma for a majority of analytes, CV was modestly increased in P100 plasma for eight analytes. Each analyte within a multiplex produced independent measurement characteristics, complicating selection of sample type for individual multiplexes.ConclusionsThere were notable detectability and measurability differences between serum and plasma. Multiplexing may not be ideal if large reliability differences exist across analytes measured within the multiplex, especially if values differ based on sample type. For some analytes, the large CV should be considered during experimental design, and the use of duplicate and/or triplicate samples may be necessary. These results should prove useful for studies evaluating selection of samples for evaluation of potential blood biomarkers.

Highlights

As a part of the longitudinal Chronic Obstructive Pulmonary Disease (COPD) study, Subpopulations and Intermediate Outcome Measures in COPD study (SPIROMICS), blood samples are being collected from 3200 subjects with the goal of identifying blood biomarkers for sub-phenotyping patients and predicting disease progression
It is well-appreciated that some blood analytes are more reliably measured in one sample type compared to others, e.g., serum versus plasma, and that absolute levels of analytes can vary depending upon the nature of blood processing [2,3,4,5]
Reliability and coefficient of variation (CV) are similar across blood sample types, with important exceptions The majority of analytes produced similar results in all sample types, both based on detection and on measurements of reliability and CV between duplicate samples (Figures 1, 2, and 3; Additional file 2: Table S2, Additional file 3: Figure S1)

Summary

Introduction

As a part of the longitudinal Chronic Obstructive Pulmonary Disease (COPD) study, Subpopulations and Intermediate Outcome Measures in COPD study (SPIROMICS), blood samples are being collected from 3200 subjects with the goal of identifying blood biomarkers for sub-phenotyping patients and predicting disease progression. Blood analytes will be measured to determine whether they may provide a picture of COPD clinical phenotypes relevant to the two broad goals of the study. It is well-appreciated that some blood analytes are more reliably measured in one sample type compared to others, e.g., serum versus plasma, and that absolute levels of analytes can vary depending upon the nature of blood processing [2,3,4,5]. Platelet activation can affect measured levels of analytes in plasma, despite the addition of additives that prevent clot formation This effect is due to release of the analyte from the platelets during processing [6]. Protein/analyte degradation during sample preparation and storage can affect analyte measurements

Methods

Results

Conclusion