Related Experiment Video
Updated: Feb 19, 2026
Lumican Extraction from Amniotic Membrane and Determination of its Storage Temperature
Published on: October 14, 2022
Effects of freezer storage time on levels of complement biomarkers
Angharad R Morgan1, Caroline O'Hagan2, Samuel Touchard2
1Division of Infection and Immunity, School of Medicine, Cardiff University, Heath Park, CF14 4XN, Cardiff, UK. morgana38@cardiff.ac.uk.
Insights
Complement analyte stability varies with long-term -80°C storage. Storage time impacts most complement biomarker concentrations, influencing disease association studies.
Area of Science:
- Biochemistry
- Immunology
- Clinical Chemistry
Background:
- Long-term stability of complement analytes at -80°C is not well-established.
- Investigated 17 complement biomarkers and C-reactive protein (CRP) in 720 plasma samples stored for 6.6-10.6 years at -80°C.
Purpose of the Study:
- To assess the impact of long-term freezer storage duration on complement biomarker concentrations.
- To determine if storage time acts as a significant co-variable in complement analysis.
Main Methods:
- Utilized solid-phase enzyme immunoassays, including MesoScale Discovery multiplex assays and single-plex ELISAs.
- Analyzed 720 plasma samples with varying storage durations (6.6-10.6 years) at -80°C.
- Performed post hoc analysis to evaluate co-variables, specifically freezer storage time.
Main Results:
- Storage time significantly correlated with measured concentrations for most complement analytes (14 out of 17).
- Positive correlations observed for C3, FI, FB, FD, C5, sCR1, C3a, iC3b, Bb, and TCC.
- Negative correlations observed for FH, C1q, and C1 inhibitor. C4, C9, sCR2, clusterin, and CRP showed no significant correlation.
Conclusions:
- Storage duration is a critical co-variable affecting complement biomarker levels.
- Consideration of storage time is essential for accurate analysis of complement biomarker associations with disease and other outcomes.
Background:
There is uncertainty regarding how stable complement analytes are during long-term storage at - 80 °C. As part of our work program we have measured 17 complement biomarkers (C1q, C1 inhibitor, C3, C3a, iC3b, C4, C5, C9, FB, FD, FH, FI, TCC, Bb, sCR1, sCR2, Clusterin) and the benchmark inflammatory marker C-reactive protein (CRP) in a large set of plasma samples (n = 720) that had been collected, processed and subsequently stored at - 80 °C over a period of 6.6-10.6 years, prior to laboratory analysis. The biomarkers were measured using solid-phase enzyme immunoassays with a combination of multiplex assays using the MesoScale Discovery Platform and single-plex enzyme-linked immunosorbent assays (ELISAs). As part of a post hoc analysis of extrinsic factors (co-variables) affecting the analyses we investigated the impact of freezer storage time on the values obtained for each complement analyte.
Results:
With the exception of five analytes (C4, C9, sCR2, clusterin and CRP), storage time was significantly correlated with measured plasma concentrations. For ten analytes: C3, FI, FB, FD, C5, sCR1, C3a, iC3b, Bb and TCC, storage time was positively correlated with concentration and for three analytes: FH, C1q, and C1 inhibitor, storage time was negatively correlated with concentration.
Conclusions:
The results suggest that information on storage time should be regarded as an important co-variable and taken into consideration when analysing data to look for associations of complement biomarker levels and disease or other outcomes.
