Transfusion and Apheresis Science 50 (2014) 92–94
Contents lists available at ScienceDirect
Transfusion and Apheresis Science journal homepage: www.elsevier.com/locate/transci
Case Report
Neutralization positive but apparent false-positive hepatitis B surface antigen in a blood donor following influenza vaccination Mark Bigham a,⇑, Arjuna Ponnampalam b a b
Canadian Blood Services, BC & Yukon Centre, Vancouver, British Columbia, Canada Department of Pathology, University of Manitoba, Winnipeg, Manitoba, Canada
a r t i c l e
i n f o
Article history: Received 26 August 2013 Accepted 29 October 2013
Keywords: Influenza Vaccine False-positive HBsAg
a b s t r a c t We report a case of transient, confirmed positive hepatitis B surface antigen (HBsAg) in a 25 year old long term Canadian Blood Services (CBS) donor, who reported receiving 2011–2012 seasonal trivalent (A/H1N1, A/H3N2, Influenza B) inactivated influenza vaccine two days before donation. To our knowledge, this report is the first published case implicating influenza vaccine as a possible factor in false-positive HBsAg test results. Seasonal incidence of repeat-reactive HBsAg among CBS donors suggests a potential contributory role of influenza vaccine or community acquired infection. We speculate that influenza vaccine may rarely be associated with sporadic, transient, false-positive HBsAg results. Ó 2013 Elsevier Ltd. All rights reserved.
1. Introduction Highly sensitive laboratory screening tests for blood borne infections such as Hepatitis B Virus (HBV) are a vital part of transfusion medicine safety. HBV is a lipid enveloped, double stranded DNA virus, and during acute and chronic HBV infection, hepatitis B surface antigen (HBsAg) expressed on the viral envelope is typically detectable by routine blood donor screening serologic testing. In addition to routine initial donor screening of HBV DNA by Roche Cobas TaqScreen MPX (Roche Molecular Diagnostics, Pleasanton, CA) and hepatitis B core antibody by ABBOTT PRISM HBcore chemiluminescent (ChLIA) assay (Abbott Laboratories, Abbott Park IL), Canadian Blood Services (CBS) undertakes routine donor HBsAg screening using the ABBOTT PRISM HBsAg chemiluminescent (ChLIA) assay (Abbott Laboratories, Abbott Park IL). In event of a reactive HBsAg test result on an initial donor screening test, CBS performs two repeat tests using the same specimen and assay. If either repeat test is also reactive ⇑ Corresponding author. Address: Canadian Blood Services, BC and Yukon Centre, 4750 Oak Street, Vancouver, British Columbia V4A 5S2, Canada. Tel.: +1 604 707 3505; fax: +1 604 875 8004. E-mail address: [email protected] (M. Bigham). 1473-0502/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.transci.2013.10.008
(i.e. ‘‘repeat reactive’’), then confirmatory testing is performed using the ABBOTT PRISM HBsAg confirmatory assay, a qualitative ChLIA assay that is designed to confirm presence of HBsAg by specific antibody neutralization [1]. In this case, a 25 year old CBS repeat blood donor was found to have apparent false-reactive HBsAg screening and confirmatory test results following routine immunization with 2011/12 inactivated, trivalent, seasonal influenza vaccine. Prior influenza vaccination has been associated with false-reactive antibody tests to HIV, Hepatitis C Virus and HTLV [2,3]; however, to the authors’ knowledge, this report represents the first published case report where influenza vaccine is implicated as a likely cause of transient, repeat-reactive HBsAg screening and positive confirmatory HBsAg neutralization assay results. We further explored a hypothesis that influenza virus antigens (either wild influenza virus or inactivated influenza virus vaccine) may be associated with false-reactive HBsAg test results by examining seasonal variation in incidence of such results. 2. Materials and methods The donor’s clinical history and results of screening questionnaire and laboratory tests were reviewed.
93
M. Bigham, A. Ponnampalam / Transfusion and Apheresis Science 50 (2014) 92–94
3. Results The donor is a 25 year old female who was a regular, repeat donor at CBS since 2003. Her past donations were unremarkable for any high risk behavior or donor laboratory test anomaly. She had been immunized against HBV as a pre-adolescent in grade 6 (approximately 14 years prior to the index donation). Two days prior to the index donation in late October 2011, she received the 2011– 2012 seasonal trivalent (A/H1N1, A/H3N2 and B) inactivated split virion influenza vaccine, Fluviral (ID Biomedical Corp of Quebec, Ste-Foy, QU) at her physician’s office, without any reported reactions. On the day of donation she did not report any symptomatic illness or any recent high risk activity for transmissible infections. Her previous donation was 56 days prior to the index donation, at which time all three routine donor hepatitis B screening tests were negative. The HBsAg screening test performed on index donation was found to be repeatedly reactive with serial sample cutoff (S/CO) values of 1.27, 1.44 and 1.28. Both anti-HBc and HBV-DNA tests were negative. All other routine donor screening tests were negative, including nucleic acid tests for human immunodeficiency viruses type 1 (HIV-1) and type 2 (HIV-2), hepatitis C virus, and West Nile virus, and serologic assays for antibodies to syphilis, human T-lymphotropic viruses type 1 (HTLV-1) and type 2 (HTLV-2), and hepatitis C virus. Cytomegalogvirus (CMV) antibodies were also not detected. Subsequent HBsAg confirmatory testing demonstrated a confirmed positive for HBsAg, with 53.55% neutralization [1]. Hepatitis B surface antibody (anti-HBs) was documented at 55 mIU/ml. Repeat testing two weeks following the donation by her family physician demonstrated non-reactivity for both HBsAg and anti-HBc. Anti-HBs on re-testing was 38.7 mIU/ml. Fig. 1 illustrates the seasonal distribution of cumulative, repeat-reactive HBsAg donations to CBS between January 2006 and December 2011 [5]. There is a significant seasonal variation in incidence (v2 = 9.199, df = 3, p = 0.027), with higher incidence of HBsAg-reactive screening tests during fall and winter months.
4. Discussion This case report describes an apparent transient, falsepositive HBsAg neutralization test result, occurring in temporal proximity to immunization with seasonal trivalent influenza vaccine.
The most common reason for a clinical false-positive HBsAg confirmatory test result (i.e. with no other corroborative laboratory, epidemiological or clinical evidence of underlying HBV infection) is hepatitis B vaccination within a few weeks prior to donating [6,7]. In this context, the HBsAg screening and confirmatory assays detect vaccinederived recombinant HBsAg, so this is not an analytic false-reactive test result. Transient vaccine-associated antigenemia may persist for up to several weeks following an immunization – a timeframe consistent with the nonreactive HBsAg test result obtained two weeks following donation in this case report [8]. Anti-nuclear antibody and influenza vaccine may also reportedly interfere with both screening and confirmatory HBsAg assays [9]. In this case, we postulate that split influenza virions in the influenza vaccine may have presented one or more binding site epitopes sufficiently mimicking HBsAg, to bind to the microparticle-bound mouse monoclonal anti-HBs employed in the ABBOTT PRISM HBsAg ChLIA screening and neutralization assays, resulting in cross-reactivity. The higher incidence of repeat-reactive HBsAg tests in Canadian Blood Services donation during the fall and winter months is consistent with this hypothesis, although this seasonal pattern also reflects the epidemiology of other prevalent community acquired viral respiratory and gastrointestinal illnesses. It is also consistent with a higher incidence of false-reactive blood donor screening test results for antibodies to HIV, hepatitis C virus and Human T-Lymphotrophic Virus type 1 (anti-HTLV-I) noted during the fall season and possibly associated with recent prior influenza vaccination [10]. Numerous potential confounders unrelated to HBV infection have been reported in association with repeatreactive HBsAg screening test results that are not confirmed by the confirmatory neutralization assay, including: a wide range of anti-viral antibodies (e.g. Cytomegalovirus, Epstein Barr virus, herpes simplex virus, hepatitis A and C viruses, HIV-1 and -2 viruses, HTLV-I and -II viruses, and rubella virus); anti-parasite antibodies (e.g. toxoplasmosis); syphilis antibodies; autoimmune markers (e.g. antinuclear antibody and rheumatoid factor); pregnancy; non-viral liver disease; hypertriglyceridemia; hypergammaglobulinemia; and receipt of influenza
Number of Repeat Reactive HBsAg donations
Additional relevant health and vaccination information was obtained by contacting the donor. Follow-up laboratory tests were obtained through collaboration with the donor’s primary care physician. Seasonal variability of repeat reactive HBsAg test results among Canadian Blood Services donations was examined using donor test data provided by Canadian Blood Services’ National Epidemiology and Surveillance Department [4]. Seasonal variation was statistically assessed by Chi-square test (Microsoft Excel 2002, Redmond, WA).
250
208
205 200
177 151
150 100 50 0
Q1 (Jan-Mar)
Q2 (Apr-Jun)
Q3 (Jul-Sep)
Q4 (Oct-Dec)
Calendar Year Quarter Fig. 1. Aggregate Canadian Blood Services repeat-reactive HBsAg donations by calendar year quarter, January 2006–December 2011 [5].
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M. Bigham, A. Ponnampalam / Transfusion and Apheresis Science 50 (2014) 92–94
vaccine [1]. Nevertheless, in most cases of a non-confirmed, repeat reactive HBsAg screening test result, a specific cause is not identified. Clinical false-positive HBsAg confirmatory test results occur less frequently than with the screening assay; some cases are attributed to laboratory error due to handling, storage or procedural deviations, equipment malfunction or material (e.g. reagent) contamination. The ABBOTT PRISM HBsAg confirmatory assay product monograph indicates a number of similar factors associated with falsereactive HBsAg screening tests have also been associated with false-positive results by HBsAg confirmatory neutralization assay, including a number of antiviral antibodies (e.g. hepatitis C, HIV-1 and -2); non-viral liver disease; pregnancy; and receipt of influenza vaccine [1]. However, most such cases of false-positive HBsAg confirmatory test results that are subsequently determined to reflect clinical false-positive results, also go unexplained. Fortunately, the paucity of reported potential influenza vaccine-associated false-reactive HBsAg test results in blood donors does not suggest a need to change the current 2 day donor deferral following immunization with inactivated influenza vaccine that is employed at Canadian Blood Services. In the case reported here, based on the repeat reactivity of the screening test and positive confirmatory test for HBsAg, the donor was indefinitely deferred from future blood donations to Canadian Blood Services. Although it is possible that such infrequent occurrences could be addressed through a donor re-entry program, the fact that this was a neutralization assay ‘‘confirmed’’ positive result, and with no recent, prior hepatitis B vaccination history, might pose significant hurdles for regulatory approval to retest for possible donor re-entry. In conclusion, the authors believe this to be the first published case report where recent prior influenza vaccine is implicated as a probable cause of a repeat-reactive
HBsAg screening assay and positive HBsAg neutralization assay in a blood donor. Acknowledgments Ms. Darlene Gagne (CBS Regional Donor Test Laboratory, Calgary, AB) and Mr. Vito Scalia (CBS National Test Laboratory, Ottawa, ON), kindly provided S/CO data. Mr. Scalia also kindly provided historical data on CBS donor repeat-reactive HBsAg test data shown in Fig. 1. References [1] ABBOTT Laboratories. Antibody to Hepatitis B Surface Antigen (Human) ABBOTT PRISM HBsAg Confirmatory Assay product monograph. #34-4213/R7. 2002. [2] MacKenzie WR, Davis JP, Peterson DE, et al. Multiple false-positive serologic tests for HIV, HTLV-1, and hepatitis C following influenza vaccination, 1991. JAMA 1992;268(8):1015–7. [3] Simonsen L, Buffington J, Shapiro CN, et al. Multiple false reactions in viral antibody screening assays after influenza vaccination. Am J Epidemiol 1995;141(11):1089–96. [4] Canadian Blood Services. National Epidemiology and Surveillance Department. Transmissible Disease Surveillance. Time Trends and Current Prevalence Rates 2011. Unpublished. 2012. [5] Canadian Blood Services. National Test Laboratory, Ottawa ON. Unpublished. 2011. [6] Otag F. False positive HBsAg result in blood donors due to administration of three different recombinant DNA Hepatitis B vaccines. Vaccine 2003;21:3734–7. [7] Dow BC, Yates P, Galea G, Munro H, et al. Hepatitis B vaccines may be mistaken for confirmed hepatitis B surface antigen-positive blood donors. Vox Sang 2002;82(1):15–7. [8] Lunn ER, Hoggarth BJ, Cook WJ. Prolonged hepatitis B surface antigenemia after vaccination. Pediatrics 2000;105(6):E81. [9] Popp C, Krams D, Beckert C, et al. HBsAg blood screening and diagnosis: performance evaluation of the ARCHITECT HBsAg qualitative and ARCHITECT HBsAg qualitative confirmatory assays. Diagn Microbiol Infect Dis 2011;70(4):479–85. [10] Buffington J, Shapiro CN, Holman RC, et al. Multiple unconfirmedreactive screening tests for viral antibodies among blood donors. Transfusion 1994;34(5):371–5.
Contents lists available at ScienceDirect
Transfusion and Apheresis Science journal homepage: www.elsevier.com/locate/transci
Case Report
Neutralization positive but apparent false-positive hepatitis B surface antigen in a blood donor following influenza vaccination Mark Bigham a,⇑, Arjuna Ponnampalam b a b
Canadian Blood Services, BC & Yukon Centre, Vancouver, British Columbia, Canada Department of Pathology, University of Manitoba, Winnipeg, Manitoba, Canada
a r t i c l e
i n f o
Article history: Received 26 August 2013 Accepted 29 October 2013
Keywords: Influenza Vaccine False-positive HBsAg
a b s t r a c t We report a case of transient, confirmed positive hepatitis B surface antigen (HBsAg) in a 25 year old long term Canadian Blood Services (CBS) donor, who reported receiving 2011–2012 seasonal trivalent (A/H1N1, A/H3N2, Influenza B) inactivated influenza vaccine two days before donation. To our knowledge, this report is the first published case implicating influenza vaccine as a possible factor in false-positive HBsAg test results. Seasonal incidence of repeat-reactive HBsAg among CBS donors suggests a potential contributory role of influenza vaccine or community acquired infection. We speculate that influenza vaccine may rarely be associated with sporadic, transient, false-positive HBsAg results. Ó 2013 Elsevier Ltd. All rights reserved.
1. Introduction Highly sensitive laboratory screening tests for blood borne infections such as Hepatitis B Virus (HBV) are a vital part of transfusion medicine safety. HBV is a lipid enveloped, double stranded DNA virus, and during acute and chronic HBV infection, hepatitis B surface antigen (HBsAg) expressed on the viral envelope is typically detectable by routine blood donor screening serologic testing. In addition to routine initial donor screening of HBV DNA by Roche Cobas TaqScreen MPX (Roche Molecular Diagnostics, Pleasanton, CA) and hepatitis B core antibody by ABBOTT PRISM HBcore chemiluminescent (ChLIA) assay (Abbott Laboratories, Abbott Park IL), Canadian Blood Services (CBS) undertakes routine donor HBsAg screening using the ABBOTT PRISM HBsAg chemiluminescent (ChLIA) assay (Abbott Laboratories, Abbott Park IL). In event of a reactive HBsAg test result on an initial donor screening test, CBS performs two repeat tests using the same specimen and assay. If either repeat test is also reactive ⇑ Corresponding author. Address: Canadian Blood Services, BC and Yukon Centre, 4750 Oak Street, Vancouver, British Columbia V4A 5S2, Canada. Tel.: +1 604 707 3505; fax: +1 604 875 8004. E-mail address: [email protected] (M. Bigham). 1473-0502/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.transci.2013.10.008
(i.e. ‘‘repeat reactive’’), then confirmatory testing is performed using the ABBOTT PRISM HBsAg confirmatory assay, a qualitative ChLIA assay that is designed to confirm presence of HBsAg by specific antibody neutralization [1]. In this case, a 25 year old CBS repeat blood donor was found to have apparent false-reactive HBsAg screening and confirmatory test results following routine immunization with 2011/12 inactivated, trivalent, seasonal influenza vaccine. Prior influenza vaccination has been associated with false-reactive antibody tests to HIV, Hepatitis C Virus and HTLV [2,3]; however, to the authors’ knowledge, this report represents the first published case report where influenza vaccine is implicated as a likely cause of transient, repeat-reactive HBsAg screening and positive confirmatory HBsAg neutralization assay results. We further explored a hypothesis that influenza virus antigens (either wild influenza virus or inactivated influenza virus vaccine) may be associated with false-reactive HBsAg test results by examining seasonal variation in incidence of such results. 2. Materials and methods The donor’s clinical history and results of screening questionnaire and laboratory tests were reviewed.
93
M. Bigham, A. Ponnampalam / Transfusion and Apheresis Science 50 (2014) 92–94
3. Results The donor is a 25 year old female who was a regular, repeat donor at CBS since 2003. Her past donations were unremarkable for any high risk behavior or donor laboratory test anomaly. She had been immunized against HBV as a pre-adolescent in grade 6 (approximately 14 years prior to the index donation). Two days prior to the index donation in late October 2011, she received the 2011– 2012 seasonal trivalent (A/H1N1, A/H3N2 and B) inactivated split virion influenza vaccine, Fluviral (ID Biomedical Corp of Quebec, Ste-Foy, QU) at her physician’s office, without any reported reactions. On the day of donation she did not report any symptomatic illness or any recent high risk activity for transmissible infections. Her previous donation was 56 days prior to the index donation, at which time all three routine donor hepatitis B screening tests were negative. The HBsAg screening test performed on index donation was found to be repeatedly reactive with serial sample cutoff (S/CO) values of 1.27, 1.44 and 1.28. Both anti-HBc and HBV-DNA tests were negative. All other routine donor screening tests were negative, including nucleic acid tests for human immunodeficiency viruses type 1 (HIV-1) and type 2 (HIV-2), hepatitis C virus, and West Nile virus, and serologic assays for antibodies to syphilis, human T-lymphotropic viruses type 1 (HTLV-1) and type 2 (HTLV-2), and hepatitis C virus. Cytomegalogvirus (CMV) antibodies were also not detected. Subsequent HBsAg confirmatory testing demonstrated a confirmed positive for HBsAg, with 53.55% neutralization [1]. Hepatitis B surface antibody (anti-HBs) was documented at 55 mIU/ml. Repeat testing two weeks following the donation by her family physician demonstrated non-reactivity for both HBsAg and anti-HBc. Anti-HBs on re-testing was 38.7 mIU/ml. Fig. 1 illustrates the seasonal distribution of cumulative, repeat-reactive HBsAg donations to CBS between January 2006 and December 2011 [5]. There is a significant seasonal variation in incidence (v2 = 9.199, df = 3, p = 0.027), with higher incidence of HBsAg-reactive screening tests during fall and winter months.
4. Discussion This case report describes an apparent transient, falsepositive HBsAg neutralization test result, occurring in temporal proximity to immunization with seasonal trivalent influenza vaccine.
The most common reason for a clinical false-positive HBsAg confirmatory test result (i.e. with no other corroborative laboratory, epidemiological or clinical evidence of underlying HBV infection) is hepatitis B vaccination within a few weeks prior to donating [6,7]. In this context, the HBsAg screening and confirmatory assays detect vaccinederived recombinant HBsAg, so this is not an analytic false-reactive test result. Transient vaccine-associated antigenemia may persist for up to several weeks following an immunization – a timeframe consistent with the nonreactive HBsAg test result obtained two weeks following donation in this case report [8]. Anti-nuclear antibody and influenza vaccine may also reportedly interfere with both screening and confirmatory HBsAg assays [9]. In this case, we postulate that split influenza virions in the influenza vaccine may have presented one or more binding site epitopes sufficiently mimicking HBsAg, to bind to the microparticle-bound mouse monoclonal anti-HBs employed in the ABBOTT PRISM HBsAg ChLIA screening and neutralization assays, resulting in cross-reactivity. The higher incidence of repeat-reactive HBsAg tests in Canadian Blood Services donation during the fall and winter months is consistent with this hypothesis, although this seasonal pattern also reflects the epidemiology of other prevalent community acquired viral respiratory and gastrointestinal illnesses. It is also consistent with a higher incidence of false-reactive blood donor screening test results for antibodies to HIV, hepatitis C virus and Human T-Lymphotrophic Virus type 1 (anti-HTLV-I) noted during the fall season and possibly associated with recent prior influenza vaccination [10]. Numerous potential confounders unrelated to HBV infection have been reported in association with repeatreactive HBsAg screening test results that are not confirmed by the confirmatory neutralization assay, including: a wide range of anti-viral antibodies (e.g. Cytomegalovirus, Epstein Barr virus, herpes simplex virus, hepatitis A and C viruses, HIV-1 and -2 viruses, HTLV-I and -II viruses, and rubella virus); anti-parasite antibodies (e.g. toxoplasmosis); syphilis antibodies; autoimmune markers (e.g. antinuclear antibody and rheumatoid factor); pregnancy; non-viral liver disease; hypertriglyceridemia; hypergammaglobulinemia; and receipt of influenza
Number of Repeat Reactive HBsAg donations
Additional relevant health and vaccination information was obtained by contacting the donor. Follow-up laboratory tests were obtained through collaboration with the donor’s primary care physician. Seasonal variability of repeat reactive HBsAg test results among Canadian Blood Services donations was examined using donor test data provided by Canadian Blood Services’ National Epidemiology and Surveillance Department [4]. Seasonal variation was statistically assessed by Chi-square test (Microsoft Excel 2002, Redmond, WA).
250
208
205 200
177 151
150 100 50 0
Q1 (Jan-Mar)
Q2 (Apr-Jun)
Q3 (Jul-Sep)
Q4 (Oct-Dec)
Calendar Year Quarter Fig. 1. Aggregate Canadian Blood Services repeat-reactive HBsAg donations by calendar year quarter, January 2006–December 2011 [5].
94
M. Bigham, A. Ponnampalam / Transfusion and Apheresis Science 50 (2014) 92–94
vaccine [1]. Nevertheless, in most cases of a non-confirmed, repeat reactive HBsAg screening test result, a specific cause is not identified. Clinical false-positive HBsAg confirmatory test results occur less frequently than with the screening assay; some cases are attributed to laboratory error due to handling, storage or procedural deviations, equipment malfunction or material (e.g. reagent) contamination. The ABBOTT PRISM HBsAg confirmatory assay product monograph indicates a number of similar factors associated with falsereactive HBsAg screening tests have also been associated with false-positive results by HBsAg confirmatory neutralization assay, including a number of antiviral antibodies (e.g. hepatitis C, HIV-1 and -2); non-viral liver disease; pregnancy; and receipt of influenza vaccine [1]. However, most such cases of false-positive HBsAg confirmatory test results that are subsequently determined to reflect clinical false-positive results, also go unexplained. Fortunately, the paucity of reported potential influenza vaccine-associated false-reactive HBsAg test results in blood donors does not suggest a need to change the current 2 day donor deferral following immunization with inactivated influenza vaccine that is employed at Canadian Blood Services. In the case reported here, based on the repeat reactivity of the screening test and positive confirmatory test for HBsAg, the donor was indefinitely deferred from future blood donations to Canadian Blood Services. Although it is possible that such infrequent occurrences could be addressed through a donor re-entry program, the fact that this was a neutralization assay ‘‘confirmed’’ positive result, and with no recent, prior hepatitis B vaccination history, might pose significant hurdles for regulatory approval to retest for possible donor re-entry. In conclusion, the authors believe this to be the first published case report where recent prior influenza vaccine is implicated as a probable cause of a repeat-reactive
HBsAg screening assay and positive HBsAg neutralization assay in a blood donor. Acknowledgments Ms. Darlene Gagne (CBS Regional Donor Test Laboratory, Calgary, AB) and Mr. Vito Scalia (CBS National Test Laboratory, Ottawa, ON), kindly provided S/CO data. Mr. Scalia also kindly provided historical data on CBS donor repeat-reactive HBsAg test data shown in Fig. 1. References [1] ABBOTT Laboratories. Antibody to Hepatitis B Surface Antigen (Human) ABBOTT PRISM HBsAg Confirmatory Assay product monograph. #34-4213/R7. 2002. [2] MacKenzie WR, Davis JP, Peterson DE, et al. Multiple false-positive serologic tests for HIV, HTLV-1, and hepatitis C following influenza vaccination, 1991. JAMA 1992;268(8):1015–7. [3] Simonsen L, Buffington J, Shapiro CN, et al. Multiple false reactions in viral antibody screening assays after influenza vaccination. Am J Epidemiol 1995;141(11):1089–96. [4] Canadian Blood Services. National Epidemiology and Surveillance Department. Transmissible Disease Surveillance. Time Trends and Current Prevalence Rates 2011. Unpublished. 2012. [5] Canadian Blood Services. National Test Laboratory, Ottawa ON. Unpublished. 2011. [6] Otag F. False positive HBsAg result in blood donors due to administration of three different recombinant DNA Hepatitis B vaccines. Vaccine 2003;21:3734–7. [7] Dow BC, Yates P, Galea G, Munro H, et al. Hepatitis B vaccines may be mistaken for confirmed hepatitis B surface antigen-positive blood donors. Vox Sang 2002;82(1):15–7. [8] Lunn ER, Hoggarth BJ, Cook WJ. Prolonged hepatitis B surface antigenemia after vaccination. Pediatrics 2000;105(6):E81. [9] Popp C, Krams D, Beckert C, et al. HBsAg blood screening and diagnosis: performance evaluation of the ARCHITECT HBsAg qualitative and ARCHITECT HBsAg qualitative confirmatory assays. Diagn Microbiol Infect Dis 2011;70(4):479–85. [10] Buffington J, Shapiro CN, Holman RC, et al. Multiple unconfirmedreactive screening tests for viral antibodies among blood donors. Transfusion 1994;34(5):371–5.
