ReFacto AF Lab Standards

Why should a product specific lab standard be used?

Using a product specific lab standard can correct the discrepancies between the chromogenic and one-stage assay.1 The use of the ReFacto AF Laboratory Lab 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.2The chromogenic assay yields results that are higher than those observed with use of one-stage clotting assay.2

When to use the ReFacto AF Laboratory Lab 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.

 

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 1.0IU/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 from 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.

How can the ReFacto AF Laboratory Lab Standards be ordered?

Orders for ReFacto AF Lab Standards can be made via E-mail here.

The following information should be put into your request to ensure the shipment can be finalised as soon as possible:

  • Contact name (Will be included on shipment paperwork)
  • Shipping address
  • Specific delivery time
  • Telephone number (Will be included on shipment paperwork)
  • E-mail address
  • Number of ReFacto AF Laboratory standard cartons (each carton contains 10 vials)
  • The Customs’ import broker name and contact information (If applicable)

Requests for ReFacto AF Lab Standards can also be made via our ‘contact us’ form. Please fill out the form and a member of the Pfizer UK Haemophilia team will aim to respond to you within 5 working days.

Click here to contact us.

We have also put all of this information into a PDF format that can be downloaded for your reference.

Click the image below to download the PDF.

 

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 (recombinant coagulation factor VIII) Summary of Product Characteristics. Accessed: July 2020.
ReFacto AF(moroctocog alfa) Prescribing information is available here.

 

PP-REF-GBR-0205. July 2020.