False Positive HTLV Testing - Recommendations for Donor Requalification

Recommendation

7/8 May 2024

Annex 2 & Co. - GMP Compliance for Biopharmaceuticals - Live Online Training
Regulatory Requirements and Practical Implementation

As an additional part of their ongoing guideline development for the safety of blood and blood products, the FDA published a "Draft Guidance for Industry Recommendations for Requalification of Blood Donors Deferred Because of Reactive Test Results for Antibodies to Human T-Lymphotropic Virus Types I and II (anti-HTLV-I/II)". A possible requalification of deferred donors is an important topic, especially if reported data (e.g.  Stramer SL, Notari EP 4th, Zou S, Krysztof DE, Brodsky JP, Tegtmeier GE, Dodd RY. Human T-lymphotropic virus antibody screening of blood donors: rates of false-positive results and evaluation of a potential donor reentry algorithm. Transfusion 2011;51(4):692-) show an important rate of false positive testing of over 70 000 donors.

Therefore, the FDA published this draft guidance document with the aim to support "blood establishments that collect Whole Blood and blood components, with recommendations for a requalification method under 21 CFR 610.41(b) for deferred donors, based on a determination that their previous reactive test results for antibodies to human T-lymphotropic virus types I and II (anti-HTLV-I/II) were falsely positive."

In this document, the FDA clarifies the premises for an ongoing deferral as well as for a possible and acceptable requalification method or process, within the meaning of 21 CFR 610.41(b), for reentry of donors deferred because of reactive screening test results for anti-HTLV-I/II under 21 CFR 610.41(a)(1).

•  FDA recommends that individuals who were indefinitely deferred with the following test results at any time are not eligible for reentry:
  1. Positive or indeterminate for anti-HTLV-I/II with an investigational or licensed supplemental test
  2. Positive or indeterminate final interpretation with a research-use supplemental HTLV algorithm (e.g., California Department of Public Health Laboratory HTLV algorithm).
• Donors who have been indefinitely deferred may be considered for reentry if they had the following test results at the time of the donation that prompted the deferral:
  1. Negative for anti-HTLV-I/II with an investigational or licensed supplemental test 
  2. Negative final interpretation with a research-use supplemental HTLV algorithm (e.g., California Department of Public Health Laboratory HTLV algorithm) before the licensed supplemental test was available 
  3. Not further tested for anti-HTLV-I/II before the licensed supplemental test was available.

Subsequently, the document describes the recommended actions for donor re-entry as well as for the implementation and reporting for such a procedure. For more details, please read the guidance Recommendations for Requalification of Blood Donors Deferred Because of Reactive Test Results for Antibodies to Human T-Lymphotropic Virus Types I and II (anti-HTLV-I/II).