Factor Xa Activity Assay Kit (Fluorometric) (ab204711)


  • Product name

    Factor Xa Activity Assay Kit (Fluorometric)
    See all Factor Xa kits
  • Detection method

  • Sample type

    Plasma, Purified protein
  • Assay type

    Enzyme activity
  • Sensitivity

    < 1 ng
  • Assay time

    0h 40m
  • Product overview

    Factor Xa Activity Assay Kit (Fluorometric) (ab204711) utilizes the ability of Factor Xa to cleave a synthetic substrate thereby releasing a fluorophore, AMC, which can be quantified by fluorescence readers. This assay kit is simple, rapid and can detect Factor Xa activity as low as 1 ng.

    Factor Xa activity assay protocol summary:
    - add samples and standards to wells
    - add reaction mix
    - analyze with microplate reader for 30-60 min every 2-3 min

  • Notes

    Factor Xa (FXa) is the activated form of the coagulation factor X (Stuart-Power factor, thrombokinase, prothrombinase, thromboplastin, E.C. Factor X, a serine endopeptidase plays an important role at several stages of the coagulation pathway. It acts by converting prothrombin into active thrombin by complexing with activated co-factor V in the prothrombinase complex. Unfractionated heparin and various low molecular weight heparins bind to plasma cofactor antithrombin to inactivate several coagulation factors including factor Xa.

  • Platform

    Microplate reader


  • Storage instructions

    Store at -20°C. Please refer to protocols.
  • Components 100 tests
    FXa Assay Buffer 1 x 15ml
    FXa Dilution Buffer 1 x 1ml
    FXa Enzyme Standard 1 x 5µl
    FXa Substrate 1 x 200µl
  • Function

    Factor Xa is a vitamin K-dependent glycoprotein that converts prothrombin to thrombin in the presence of factor Va, calcium and phospholipid during blood clotting.
  • Tissue specificity

    Plasma; synthesized in the liver.
  • Involvement in disease

    Defects in F10 are the cause of factor X deficiency (FA10D) [MIM:227600]. A hemorrhagic disease with variable presentation. Affected individuals can manifest prolonged nasal and mucosal hemorrhage, menorrhagia, hematuria, and occasionally hemarthrosis. Some patients do not have clinical bleeding diathesis.
  • Sequence similarities

    Belongs to the peptidase S1 family.
    Contains 2 EGF-like domains.
    Contains 1 Gla (gamma-carboxy-glutamate) domain.
    Contains 1 peptidase S1 domain.
  • Post-translational

    The vitamin K-dependent, enzymatic carboxylation of some glutamate residues allows the modified protein to bind calcium.
    N- and O-glycosylated. O-glycosylated with core 1 or possibly core 8 glycans.
    The activation peptide is cleaved by factor IXa (in the intrinsic pathway), or by factor VIIa (in the extrinsic pathway).
    The iron and 2-oxoglutarate dependent 3-hydroxylation of aspartate and asparagine is (R) stereospecific within EGF domains.
  • Cellular localization

  • Information by UniProt
  • Alternative names

    • Activated factor Xa heavy chain
    • F10
    • FA10_HUMAN
    • Stuart factor
    • Stuart-Prower factor
    see all


  • Standard plot of FXa activity measured at two different emission wavelengths (450 and 460 nm) keeping the excitation at 350 nm.

  • FXa activity was measured in plasma samples in the presence and absence of a FXa inhibitor, GGACK Dihydrochloride. S = Substrate, I = Inhibitor.



ab204711 has not yet been referenced specifically in any publications.

Customer reviews and Q&As

We tested the Factor Xa Activity Assay Kit (Fluorometric) on cell culture media. Although we found 9/14 of our cell culture media samples to have FXa activity levels below the lowest standard in the more sensitive assay setup (2 ng/well or 40ng/ml), the remaining samples had FXa activity of 200.0-1439.0 ng/ml. An external FXa positive quality control tested was found to have an FXa activity level similar to that claimed by its manufacturer, and our negative quality controls universally had RFU values below the lowest assay standards.

Provision of a higher volume of FXa Substrate would be welcome to allow easier multi-channel pipetting, but in general we were quite pleased with the kit.

John Castle

Verified customer

Submitted Apr 09 2018

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