Biochemically Tracked Variability of Blood Plasma Thawed-State Exposure Times in a Multisite Collection Study

Abstract

The integrity of blood plasma/serum (P/S) specimens can be impacted by preanalytical handling and storage conditions that result in thawed-state exposures (>-30°C). We recently reported a simple dilute-and-shoot, intact-protein liquid chromatography/mass spectrometry (LC/MS) assay called DS-Cys-Albumin that quantifies cumulative exposure of P/S to thawed conditions based on the change in relative abundance of the oxidized (Scysteinylated) proteoform of albumin (S-Cys-Albumin) in the native sample to that of an aliquot of the sample intentionally driven to its maximum oxidation state. Herein, we evaluated the effect of prestorage delay and initial storage temperature on sample integrity by applying the DS-Cys-Albumin assay to a set of plasma samples (n = 413) collected under a single clinical study but from 12 different collection sites. Major differences (p < 0.0001) were observed between different groups of samples with modestly inconsistent initial handling conditions (i.e., initial processing of whole blood to plasma and placement at-80°C completed in under 3 hours, 3-13 hours, and over 17 hours). DS-Cys-Albumin was significantly inversely correlated with delay time at 4°C before centrifugation and total delay before final storage at-80°C (p < 0.0001). Samples from two collection sites had much lower DS-Cys-Albumin values relative to samples from other sites, in accordance with the fact that they were stored at-20°C for an average of 7.6 months before shipment to the central repository for final storage at-80°C. Based on the rate law for S-Cys-Albumin formation in plasma ex vivo, the average time that each plasma specimen had been exposed to the equivalent of room temperature (23°C) was back calculated from the measured DS-Cys-Albumin values. A survey of clinical analytes in P/S whose measured concentrations are sensitive to the initial handling/storage conditions documented in this study is provided and the ramifications of the plasma integrity findings from this multisite clinical study are discussed.

Effect of acupuncture on pain and substance P levels in middle-aged women with chronic neck pain

“…We primarily screened 29 participants to be enrolled in the study. After the first blood sampling ( 20 ), two participants dropped out due to perceived discomfort in blood sampling. Four participants withdrew from the study due to not being able to comply with the treatment schedule.…”

Oxidized LDL is stable in human serum under extended thawed-state conditions ranging from −20 °C to room temperature

“…To our knowledge, however, no systematic evaluation of oxLDL stability under a series of temperatures and time ranges has been conducted. The purpose of this study was to comprehensively evaluate the stability of oxLDL in human serum over time courses at 23 °C, 4 °C, and −20 °C while simultaneously measuring ΔS-Cys-Albumin—a well characterized marker of plasma/serum exposure to thawed conditions that is based on the ex vivo oxidation of albumin to S-cysteinylated albumin [35] , [36] , [37] , [38] .…”