Common questions about our human coagulation factor Luminex multiplex panel service.
What is the difference between coagulation factor antigen measurement (Luminex) and functional activity assays?
Luminex multiplex measures the protein concentration (antigen level) of each coagulation factor using capture and detection antibodies in a sandwich immunoassay format. Functional activity assays measure enzymatic or cofactor activity using clot-based or chromogenic methods. Antigen measurement reveals how much protein is present; activity measurement reveals whether that protein works. The combination of both provides the most complete picture — decreased activity with normal antigen suggests an inhibitor or dysfunctional protein; decreased activity with decreased antigen indicates impaired synthesis or consumption.
Why must I use plasma — not serum — for coagulation factor measurement?
Coagulation factors are consumed during the clotting process that generates serum. When whole blood clots in a serum tube, prothrombin is converted to thrombin, fibrinogen is converted to fibrin, Factor XIII cross-links the fibrin clot, and Factor V and VIII are activated and subsequently degraded. Serum levels of these factors reflect post-coagulation residuals and are not representative of in vivo concentrations. Citrate plasma (anticoagulated with sodium citrate) prevents in vitro coagulation, preserving factor concentrations for accurate measurement.
Which anticoagulant is preferred — citrate or EDTA — for this panel?
Citrate plasma (3.2% sodium citrate, light blue top tube) is the preferred matrix for coagulation factor measurement. Citrate reversibly chelates calcium, preventing coagulation without denaturing proteins. EDTA plasma is acceptable for most immunoassay-based antigen measurements, but EDTA irreversibly chelates calcium and magnesium, which may affect the conformation of calcium-dependent coagulation factors (Factors II, VII, IX, X, Protein C, Protein S). If EDTA plasma is the only available sample type, the panel can still be run, but we recommend standardizing to a single anticoagulant across all samples in a study.
Can the 6-plex configuration measure both pro-coagulant and anti-coagulant factors simultaneously?
Yes. The 6-plex includes pro-coagulant factors (Prothrombin, Factor VIII, Factor XIII), anticoagulant regulators (Antithrombin, Protein C), and an endothelial activation marker (vWF). Measuring accelerators (pro-coagulant) and brakes (anticoagulant) simultaneously provides a balanced assessment of the hemostatic system. This is particularly valuable in conditions like liver disease and DIC, where both systems are affected in parallel.
What is the significance of measuring Factor XIII antigen in COVID-19 research?
Factor XIII cross-links fibrin monomers to form a mechanically stable clot. Al-Tamimi et al. (2022) demonstrated that FXIII antigen is profoundly reduced in severe COVID-19 — its consumption reflects ongoing fibrin formation and cross-linking in the microvasculature, a hallmark of COVID-19-associated coagulopathy. Reduced FXIII may contribute to the paradoxical combination of thrombosis (microvascular) and bleeding risk (due to clot instability) observed in severe cases.
How customizable is this panel? Can I add or remove specific factors?
Fully customizable. The available coagulation-related targets can be combined in any configuration. If your research focuses on the vitamin K-dependent factors (Factors II, VII, IX, X, Protein C, Protein S), we can build a targeted panel. If you need D-Dimer and PAI-1 added for a comprehensive thromboinflammation profile, we can include them. Contact us with your target list for a custom panel configuration.
Can this panel replace traditional coagulation testing (PT, APTT)?
No. The Luminex coagulation factor panel measures antigen concentrations — not functional activity. It provides complementary information that enhances the interpretation of traditional coagulation tests, but it does not replace functional assays. For comprehensive hemostatic research, we recommend combining Luminex antigen measurement with functional coagulation testing. This combined approach provides both the "what" (antigen levels) and the "how well" (activity levels).
