Research ArticleResearch and Reports

Emicizumab and the Clinical Coagulation Laboratory

Michael A. Nardi
American Society for Clinical Laboratory Science April 2023, DOI: https://doi.org/10.29074/ascls.2019002204

Article Figures & Data

Figures

  • Figure 1.
    Figure 1.

    Schematic illustrations of cofactor actions of FVIIIa and a bispecific antibody promoting the interaction between FIXa and FX. (A) FVIIIa forms a complex with FIXa and supports the interaction between FIXa and FX through its binding ability to both factors on the phospholipid membrane. (B) A bispecific antibody binding to FIXa and FX would promote the interaction between FIXa and FX and exert FVIII mimetic activity on the phospholipid membrane. Reproduced under the terms of the Creative Commons Attribution license. Sampei Z, Igawa T, Soeda T, Okuyama-Nishida Y, Moriyama C, Wakabayashi T, et al.20

  • Figure 2.
    Figure 2.

    Schematics of FVIII activity assays. (A) One-stage clotting assay. (B) Chromogenic substrate assay. CaCl2, calcium chloride; CSA, chromogenic substrate assay; FII, factor II (prothrombin); FIX, factor IX; FIXa, activated FIX; FVIII, factor VIII; factor VIIIa, activated FVIII; FX, factor X; FXa, activated FX; PL, phospholipid; pNA, para-nitroanaline.

  • Figure 3.
    Figure 3.

    Normal thromboelastogram (TEG). Reproduced under the terms of STM permission guidelines (2014). Chitlur M, Young G.61

  • Figure 4.
    Figure 4.

    Typical thrombin generation assay (TGA) with relevant parameters. Reproduced with permission from the American Association for Clinical Chemistry. Tripodi A.63

Tables

  • Table 1.

    Effect of emicizumab on clinical coagulation assays

    Assays Affected by EmicizumabAssays Unaffected by Emicizumab
    APTTFibrinogen, according to Clauss
    APTT-based APCR assayThrombin Time
    APTT-based OSA factor assayPT-based OSA factor assay
    APTT-based protein C assayPT-activator based APCR
    APTT-based protein S assayBethesda assay (bovine chromogenic) for FVIII inhibitor titer
    Bethesda assay (clotting based) for FVIII inhibitor titerChromogenic assays (e.g., antithrombin, anti-Xa activity, protein C, plasminogen)
    PT (weak effect) Fibrinogen, PT-derived (weak effect)ELISA assays (e.g., plasminogen antigen, protein S antigen (free, total), D-dimer, VWF-antigen, VWF-activity, FXIII-antigen)
    Activated clotting timeGenetic tests for coagulation factors (e.g., factor V mutation, prothrombin 20210)

    APCR, activated protein C resistance; APTT, activated partial thromboplastin time; FXIII, factor XIII; OSA, one-stage clotting assay; PT, prothrombin time; VWF, von Willebrand factor; Xa, activated factor X.

    • Table 2.

      Comparison of terms for TEG 5000 and ROTEM

      TEG 5000 TermROTEM TermUnitsClot Formation Property
      Reaction time (R)Clotting time (CT)Seconds/minutesClot initiation
      Kinetic time (K)Clot formation time (CFT)Seconds/minutesClot propagation
      Alpha angleAlpha angleDegreesClot propagation
      Maximal amplitude (MA)Maximum clot firmness (MA)MillimetersClot rigidity
      Clot elastic modulus (G)Shear elastic modulus (G)Dynes/cm2Clot elasticity
    Back to top

    In this issue

    Print
    Download PDF
    Article Alerts
    Email Article
    Citation Tools
    Request Permissions
    Emicizumab and the Clinical Coagulation Laboratory
    Michael A. Nardi
    American Society for Clinical Laboratory Science Apr 2023, DOI: 10.29074/ascls.2019002204
    Twitter logo Facebook logo Mendeley logo

    Jump to section

    Keywords