Confidential donation confirmation as a alternative exclusion

SCIENTIFIC COMMENTS

Confidential donation confirmation as a alternative exclusion

Thelma T Gonçalez

Blood Systems Research Institute, San Francisco, CA, United States

^{Corresponding author}

In this issue of the Revista Brasileira de Hematologia e Hemoterapia, Loureiro et al. present their evaluation of the use of confidential donation confirmation (CDC), i.e., release of blood units from donors who have confirmed that their blood may be used for transfusion by choosing the "yes" option.⁽¹⁾

The conclusion of this case-control study is that CDC did not reduce the residual risk of transfusion-transmitted infections (TTIs) nor did it deter at-risk donors from donation. In brief, no real benefit was associated with the use of CDC.

The safety of the blood supply has been improved over the years by the progressive implementation of measures aimed at reducing the risk of TTIs. The use of voluntary nonremunerated donors, the implementation of donor education programs, the careful selection of donors interviewed before their donation using donor questionnaires and the development of sensitive laboratory screening assays have all contributed tremendously to the improvement in blood safety. Over the last decade, the use of nucleic acid amplification technology (NAT) has improved blood safety by reducing the window period and the residual risk of human immunodeficiency virus (HIV) transmission around the world.^(2,3) Nowadays, a lower prevalence of infectious diseases is observed among blood donors and the immunological window periods for these infections have been shortened remarkably.⁽³⁾ However, global and regional differences persist due to higher or lower incidences of diseases and, because of the window period, there will always be a residual risk for TTIs. The improvement in blood safety therefore requires ongoing effort within a wide range of contexts.

In 1986, the U.S. FDA recommended the use of confidential unit exclusion (CUE).⁽⁴⁾ This approach allows at-risk donors to confidentially exclude their blood from being used for transfusion. However, the use of CUE is controversial as many authors have reported that CUE has low sensitivity, a low positive predictive value^(5-7) and no proven benefit in terms of improving blood safety. Furthermore, CUE has even been associated with a small but constant loss of apparently safe donations.⁽⁷⁾ For this reason, the CUE is no longer in use in most U.S. blood banks⁽⁸⁾ However, CUE is still used or recommended in other countries, such as in the United Kingdom,⁽⁹⁾ Switzerland,⁽⁹⁾ Iran,⁽¹⁰⁾ Brazil^(11,12) and Germany.⁽⁹⁾

The use of CUE has been evaluated in countries where NAT screening is performed and where the residual risk of HIV transfusion-transmission is lower, such as in Germany and Canada and results have shown that the sensitivity and positive predictive values of CUE are very low and it has minimal impact on transfusion safety.^(9,13) Also, the researchers concluded that the efficacy and usage rate of CUE depend very much on the demographic characteristics of donors as well as the design of the CUE form and procedures.

In Brazil, NAT screening for HIV is not performed routinely by most blood banks. This results in a longer infectious window period and substantially greater residual risk of transfusion-associated transmission of HIV than in the U.S.^(2,3) and Europe.^(14,15) In Brazil, estimates of HIV incidence are approximately 10-fold higher in first-time donors than in the U.S.⁽³⁾ and Europe.⁽¹⁵⁾ A recent study by Dr. Sabino et al.⁽¹⁶⁾ showed that even with the implementation of NAT, the risk of residual HIV in Brazil will remain higher than it was in the U.S. prior to NAT screening.^(3,17) In this case, the use of CUE could potentially help exclusion of units donated during the HIV window period.⁽¹⁸⁾

The CUE or CDC approaches have been used in several Brazilian blood banks in compliance with local regulations or recommendation.⁽¹²⁾ Mendrone et al.⁽¹⁹⁾ found that, in the absence of better methods to reduce the HIV window period, the CUE option would potentially prevent only a few cases of transfusion-transmitted HIV infection. Almeida-Neto et al.⁽¹⁸⁾ demonstrated that the use of the CUE option, although resulting in a high number of discarded units, was predictive of marker-positive donation and thus appeared to contribute modestly to blood safety.

As long as no consensus has been reached on the use of CUE or CDC to prevent high risk blood donors from donating blood, the rights of the recipients to receive the safest possible blood supply should prevail. Meanwhile, blood bankers are investigating ways to improve blood safety for the community and further studies, in each locale, will be important for informed decision making about CUE, CDC or other measures. In the interest of recipients, high risk blood donors should be excluded from donating blood. Thus, the use of CUE might contribute to an improvement in the safety of blood. CUE might be even more relevant in middle- and low-income countries with high prevalence and incidence rates of HIV, in countries with high rates of prejudice and stigma against HIV positive persons, in countries where infections are not concentrated in specific at-risk populations (i.e., where donor deferral questions are not as efficient) such as sub-Saharan African countries, or in countries where costly measures to reduce the risk of TTIs (e.g., NAT testing) are not feasible and where access to alternative testing is limited. In Brazil, as NAT screening will be implemented in the entire country in the near future, larger scale studies would be useful to balance the benefit of using CUE or CDC in addition to NAT screening to reduce the number of units from risky but test-negative donors with the loss of blood units from safe donors.

Submitted: 7/12/2011

Accepted: 7/13/2011

Conflict-of-interest disclosure: The authors declare no competing financial interest

www.rbhh.org or www.scielo.br/rbhh

• 1. Loureiro FC, Oliveira CD, Carneiro-Proietti AB, Proietti FA. Confidential donation confirmatios as an alternative to confidential unit exclusion: 15 months experience of hemominas foundation. Rev Bras Hematol Hemoter. 2011;33(4):263-7.
• 2. Busch MP, Hecht FM. Nucleic acid amplification testing for diagnosis of acute HIV infection: has the time come? Aids. 2005;12(19):1317-9.
• 3. Stramer SL, Glynn SA, Kleinman SH, Strong DM, Caglioti S, Wright DJ, et al. Detection of HIV-1 and HCV infections among antibodynegative blood donors by nucleic acid-amplification testing. N Engl J Med. 2004;19(351):760-8.
• ⁴
  FDA. Memorandum to blood establishments. Addtional recommendations for reducing further the number of units of blood and plasma donated for transfusion or for further manufacture by persons at increased risk of HTKLV-II/LAV infection. 1986.
• 5. Korelitz JJ, Williams AE, Busch MP, Zuck TF, Ownby HE, Matijas LJ, et al. Demographic characteristics and prevalence of serologic markers among donors who use the confidential unit exclusion process: the Retrovirus Epidemiology Donor Study. Transfusion. 1994;34(10):870-6.
• 6. Petersen LR, Lackritz E, Lewis WF, Smith DS, Herrera G, Raimondi V, et al. The effectiveness of the confidential unit exclusion option. Transfusion. 1994;34(10):865-9.
• 7. Zou S, Notari EPt, Musavi F, Dodd RY. Current impact of the confidential unit exclusion option. Transfusion. 2004;44(5):651-7.
• ⁸
  FDA. Memorandum to blood establisment.Revised recommendation for the prevention of human immunodeficiency virus HIV transmission by blood and blood products. 1992.
• 9. Sumnig A, Konerding U, Kohlmann T, Greinacher A. Factors influencing confidential unit exclusions in blood donors. Vox Sang. 2010;98:(3Pt 1)e231-40. Epub 2009 Sep 18.
• 10. Cheraghali AM, Abolghasemi H. Improving availability and affordability of plasma-derived medicines. Biologicals. 2009;38(1):81-6.
• ¹¹
  Brazil. Resolução RDC nº 153, de 14 de junho de 2004: Determina o Regulamento Técnico para os procedimentos hemoterápicos, incluindo a coleta, o processamento, a testagem, o armazenamento, o transporte, o controle de qualidade e o uso humano de sangue, e seus componentes, obtidos do sangue venoso, do cordão umbilical, da placenta e da medula óssea Diário Oficial da União; Poder Executivo, de 24 de junho de 2004: ANVISA - Agência Nacional de Vigilância Sanitária. 2004.
• ¹²
  Brazil. Portaria MS nº 1.353-Aprova o Regulamento Técnico de Procedimentos Hemoterápicos. Diário Oficial da União; Poder Executivo, de 14 de junho de 2011: ANVISA - Agência Nacional de Vigilância Sanitária. 2011.
• 13. O'Brien SF, Fan W, Xi G, Yi QL, Goldman M. Evaluation of the confidential unit exclusion form: the Canadian Blood Services experience. Vox Sang. 2010;98(2):138-44.
• 14. Pillonel J, Laperche S. [Trends in residual risk of transfusiontransmitted viral infections (HIV, HCV, HBV) in France between 1992 and 2002 and impact of viral genome screening (Nucleic Acid Testing)]. Transfus Clin Biol. 2004;11(2):81-6.
• 15. Likatavicius G, Hamers FF, Downs AM, Alix J, Nardone A. Trends in HIV prevalence in blood donations in Europe, 1990-2004. Aids. 2007;21(8):1011-8.
• 16. Sabino ECG, Carneiro-Proietti AB, Sarr M, Ferreira JE, Sampaio D, Salles NA, Wright DJ, Custer B and Busch M, for the NHLBI Retrovirus Epidemiology Donor Study-II (REDS-II), International Component. HIV prevalence, incidence and residual risk of transmission by transfusions at REDS-II blood centers in Brazil. Transfusion. 2011; in press.
• 17. Dodd RY, Notari EPt, Stramer SL. Current prevalence and incidence of infectious disease markers and estimated window-period risk in the American Red Cross blood donor population. Transfusion. 2002;42(8):975-9.
• 18. de Almeida-Neto C, Liu J, Wright DJ, Mendrone-Junior A, Takecian PL, Sun Y, et al. Demographic characteristics and prevalence of serologic markers among blood donors who use confidential unit exclusion (CUE) in Sao Paulo, Brazil: implications for modification of CUE policies in Brazil. Transfusion. 2010;51(1):191-7.
• 19. Mendrone-Junior A, de Almeida Neto C, Pedroso MI, Sabino EC, Dorlhiac-Llacer PE, Chamone DA. Confidential unit exclusion option among seroconverters for HIV in São Paulo, Brazil. Transfusion. 2007;Suppl:101 A.

Publication Dates

• Publication in this collection
  20 Sept 2011
• Date of issue
  2011