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Click here for ReFacto AF® (moroctocog alfa) Prescribing Information. Adverse event reporting information can be found at the bottom of the page.

Why, when and how to use the ReFacto AF Laboratory Standard

Why should a product specific laboratory standard be used?

Using a product specific laboratory standard can correct the discrepancies between the chromogenic and one-stage assay.1 The use of the ReFacto AF Laboratory Standard allows for consistent results regardless of assay type.

When monitoring patients' factor VIII activity levels during treatment with ReFacto AF, the use of a chromogenic substrate assay is recommended.2 The chromogenic assay yields results that are higher than those observed with use of the one-stage clotting assay.2

When to use the ReFacto AF Laboratory Standard

The ReFacto AF Laboratory Standard was created for use with the one-stage clotting assay (or the chromogenic assay), when testing plasma samples from patients receiving ReFacto AF. It can be used exactly as you would use a normal (plasma-based) laboratory standard.

The one-stage assay process.

How to prepare the ReFacto AF Laboratory Standard

There are 3 steps involved in preparing the ReFacto AF Laboratory Standard

Step 1

  • Reconstitute the ReFacto AF Laboratory Standard at room temperature using 1.0mL of sterile water
  • After reconstitution, the vial contents should be transferred to a plastic tube with a stopper
  • The reconstituted ReFacto AF Laboratory Standard solution should be maintained at room temperature and then used within 2 hours *

*The reconstituted ReFacto AF Laboratory Standard is stable for 2 hours

Unopen vials should be stored at -20oC

Do not use the vial if there is a lack of vacuum when opening

Step 2

  • The ReFacto AF Laboratory Standard should be prediluted in factor VIII-deficient (haemophilic or artificially depleted) plasma containing normal functional levels of von Willebrand factor to yield a 1.0 IU/mL solution
  • The prepared standard should be used once and discarded
  • DO NOT REFREEZE

Step 3

  • The working ReFacto AF Laboratory Standard solution can now be used to create a standard curve for analysis of plasma samples form patients treated with ReFacto AF
  • Once the standard curve is established, analysis of plasma samples from patients treated with ReFacto AF may begin
  • Discard all unused materials following universal precautions

Important Information

The standard is to be used to measure ReFacto AF levels and is not to be used for performing diagnostic FVIII tests. It should NOT be administered to patients. It is not intended for testing patients with normal levels of FVIII:C or patients receiving other FVIII concentrates other than ReFacto AF.

ReFacto AF Laboratory Standard PDF

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References
  1. Ingerslev J, Jankowski MA, Weston SB, et al. Collaborative field study on the utility of a BDD factor VIII concentrate standard in the estimation of BDDr factor VIII:C activity in hemophilic plasma using one-stage clotting assays. J Thromb Haemost. 2004;2: 632-8.
  2.  ReFacto AF (moroctocog alfa) Summary of Product Characteristics: https://www.medicines.org.uk/emc/product/6558/smpc
PP-REF-GBR-0201. March 2021

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