Najib Aziz1, Roger Detels2, Joshua J Quint2, Qian Li3, David Gjertson4, Anthony W Butch5. 1. Department of Epidemiology, UCLA, Los Angeles, CA 90095-1772, United States; Fielding School of Public Health, UCLA, Los Angeles, CA 90095-1772, United States. Electronic address: naziz@mednet.ucla.edu. 2. Department of Epidemiology, UCLA, Los Angeles, CA 90095-1772, United States; Fielding School of Public Health, UCLA, Los Angeles, CA 90095-1772, United States. 3. Department of Biostatistics, UCLA, Los Angeles, CA 90095-1772, United States; Fielding School of Public Health, UCLA, Los Angeles, CA 90095-1772, United States. 4. Department of Biostatistics, UCLA, Los Angeles, CA 90095-1772, United States; David Geffen School of Medicine, UCLA, Los Angeles, CA 90095-1772, United States. 5. The Department of Pathology and Laboratory Medicine, UCLA, Los Angeles, CA 90095-1713, United States; David Geffen School of Medicine, UCLA, Los Angeles, CA 90095-1772, United States.
Abstract
BACKGROUND: Biomarkers such as cytokines, chemokines, and soluble activation markers can be unstable when processing of blood is delayed. The stability of various biomarkers in serum and plasma was investigated when unprocessed blood samples were stored for up to 24h at room and refrigerator temperature. METHODS: Blood was collected from 16 healthy volunteers. Unprocessed serum, EDTA and heparinized blood was stored at room (20-25°C) and refrigerator temperature (4-8°C) for 0.5, 2, 4, 6, 8, and 24h after collection before centrifugation and separation of serum and plasma. Samples were batch tested for various biomarkers using commercially available immunoassays. Statistically significant changes were determined using the generalized estimating equation. RESULTS: IFN-γ, sIL-2Rα, sTNF-RII and β2-microglobulin were stable in unprocessed serum, EDTA and heparinized blood samples stored at either room or refrigerator temperature for up to 24h. IL-6, TNF-α, MIP-1β and RANTES were unstable in heparinized blood at room temperature; TNF-α, and MIP-1β were unstable in unprocessed serum at room temperature; IL-12 was unstable in unprocessed serum at refrigerator temperature; and neopterin was unstable in unprocessed EDTA blood at room temperature. IL-1ra was stable only in unprocessed serum at room temperature. CONCLUSION: All the biomarkers studied, with the exception of IL-1ra, were stable in unprocessed EDTA blood stored at refrigerator temperature for 24h. This indicates that blood for these biomarkers should be collected in EDTA and if delays in processing are anticipated the unseparated blood should be stored at refrigerator temperature until processing.
BACKGROUND: Biomarkers such as cytokines, chemokines, and soluble activation markers can be unstable when processing of blood is delayed. The stability of various biomarkers in serum and plasma was investigated when unprocessed blood samples were stored for up to 24h at room and refrigerator temperature. METHODS: Blood was collected from 16 healthy volunteers. Unprocessed serum, EDTA and heparinized blood was stored at room (20-25°C) and refrigerator temperature (4-8°C) for 0.5, 2, 4, 6, 8, and 24h after collection before centrifugation and separation of serum and plasma. Samples were batch tested for various biomarkers using commercially available immunoassays. Statistically significant changes were determined using the generalized estimating equation. RESULTS: IFN-γ, sIL-2Rα, sTNF-RII and β2-microglobulin were stable in unprocessed serum, EDTA and heparinized blood samples stored at either room or refrigerator temperature for up to 24h. IL-6, TNF-α, MIP-1β and RANTES were unstable in heparinized blood at room temperature; TNF-α, and MIP-1β were unstable in unprocessed serum at room temperature; IL-12 was unstable in unprocessed serum at refrigerator temperature; and neopterin was unstable in unprocessed EDTA blood at room temperature. IL-1ra was stable only in unprocessed serum at room temperature. CONCLUSION: All the biomarkers studied, with the exception of IL-1ra, were stable in unprocessed EDTA blood stored at refrigerator temperature for 24h. This indicates that blood for these biomarkers should be collected in EDTA and if delays in processing are anticipated the unseparated blood should be stored at refrigerator temperature until processing.
Authors: Stephanie L Baer; Rhonda E Colombo; Maribeth H Johnson; Sushama Wakade; Gabriela Pacholczyk; Cheryl Newman-Whitlow; Stuart A Thompson; Michael S Saag; Jeffrey N Martin; Michelle Floris-Moore; Lei Huang; Andrew L Mellor Journal: J Investig Med Date: 2021-04-19 Impact factor: 2.895