For accurate complement analysis, it is important that not only the correct technique is used but also that pre-analytical sample handling is performed in an appropriate manner to avoid erroneous results.  Our senior scientist Erik Toonen, together with a group of professionals, has performed a literature search using the Pubmed/MEDLINE database focusing on studies measuring key complement components in human blood samples that were published between February 2017 and February 2022. The identified studies were reviewed whether they had used the correct sample type and techniques for their analyses. Learn about his findings below.

Desktop analysis

A total of 92 out of 376 studies were selected for full-text analysis. Forty-five studies (49%) were identified as using the correct sample type and techniques for their complement analyses, while 25 studies (27%) did not use the correct sample type or technique. For 22 studies (24%), it was not specified which sample type was used.

A substantial part of the reviewed studies did not use the appropriate sample type for assessing complement activation or did not mention which sample type was used. This deviation from the standardized procedure can lead to misinterpretation of complement biomarker levels and hampers proper comparison of complement measurements between studies. Therefore, this study underlines the necessity of general guidelines for accurate and recommended procedure.

Appropriate sample type

To choose the correct sample type, it is essential to begin by distinguishing whether you are assessing the overall function of the complement system or the specific components. When your focus is on assessing complement function, it is crucial to utilize complement-preserved serum. Conversely, when you intend to evaluate individual complement components, EDTA-plasma should be employed. The flowchart presented below assists you in determining the suitable sample type and guides you toward the most suitable sample pretreatment method.

Appropriate technique

If you wish to determine which technique or assay is best suited for your research, it is also essential to identify whether you are conducting an assessment of complement function or an assessment of individual complement components. When assessing complement function, the most suitable techniques include hemolytica activity assays, functional ELISA or functionalized liposomes. For the evaluation of individual complement components, nephelometry, ELISAs, Multiplex assays, OMICS/protein arrays, or mass spectrometry are the preferred methods.

You can find optional guidelines below or reach out to us directly to help you.

Refererence:
Brandwijk RJMGE, Michels MAHM, van Rossum M, de Nooijer AH, Nilsson PH, de Bruin WCC, Toonen EJM. Pitfalls in complement analysis: A systematic literature review of assessing complement activation. Front Immunol. 2022 Oct 18;13:1007102. doi: 10.3389/fimmu.2022.1007102. PMID: 36330514; PMCID: PMC9623276.