Potential deferral criteria predictive of human immunodeficiency virus positivity among blood donors in Thailand

Background: To develop deferral criteria to prevent human immunodeficiency virus (HIV) transmission by recently infected blood donors in the seronegative “window” phase, routine data on donors at a university hospital were examined for factors predicting seropositivity. Study Design and Methods: Records of all 281 HIV- positive blood donors from August 1987 through September 1991 were retrospectively compared with those of 1076 randomly selected control donors matched only by year of donation. Four controls were selected for each HIV-positive donor. Results: The prevalence of HIV in 102,684 donor units during the period rose from 0.02 percent in 1987 to 0.52 percent in 1991. Multivariable analysis revealed that male sex (odds ratio [OR] = 26.4), VDRL test positivity (OR = 3.0), age 21 to 30 years (OR = 2.2; referent: 16–20-year-old group), and replacement donorship (OR = 1.4; referent: voluntary donors) were independent factors significantly associated with HIV positivity among these donors (p < 0.05). Since replacement donorship cannot be avoided, only male sex, age 21 to 30 years, and VDRL test positivity were considered as potential criteria. When these findings were extrapolated to all donors in 1990 and 1991, those with all three or only two (excluding VDRL test, because the results are known only after donation) of these high- risk factors had HIV positivity probabilities of 2.2 and 1.0 percent, respectively. These probabilities were, respectively, 4.9 times (95% CI: 2.9 8.3) and 4.1 times (3.1, 5.4) the risk among other donors. However, applying such criteria would have eliminated 1.5 and 31.2 percent, respectively, of all HIV-negative donors in 1990 and 1991. The latter deferral proportion is too high to be acceptable. Conclusion: In Thailand, improved donor deferral criteria addressing sexual risk factors could lead to decreased probability of window-period donation, with an acceptable rate of deferral. Additional p24 antigen testing may be indicated for donors at increased risk for HIV infection, specifically, men aged 21 to 30.     

Profile of blood donors with serologic tests reactive for the presence of syphilis in São Paulo, Brazil

BACKGROUND: Syphilis screening of blood donors is a common practice worldwide, but very little is known about the meaning of a positive serologic test for syphilis in blood donors and the risk profile of these donors. The aim of this study was to determine the demographic characteristics and risk behaviors of blood donors with recent and past syphilis and their implications for blood bank testing and deferral strategies.
STUDY DESIGN AND METHODS: Demographic characteristics, category of donation, number of previous donations, sexual behavior, and history of sexually transmitted diseases were reviewed comparing blood donors with recent and past syphilis from January 1, 1999, to December 31, 2003.
RESULTS: A total of 2439 interviews were reviewed, including 2161 (88.6%) donors with past and 278 (11.4%) with recent syphilis infection. Factors associated with recent infection included younger age (≤20 years odds ratio [OR], 36.5; 95% confidence interval [CI], 15.8-84.1), two previous donations (OR, 2.7; 95% CI, 1.9-3.9), male-male sex (homosexual OR, 8.2; 95% CI, 3.2-20.8; and bisexual OR, 11.4; 95% CI, 3.6-36.3), two or more partners in the past 12 months (OR, 2.3; 95% CI, 1.3-4.0), symptoms for syphilis (OR, 4.5; 95% CI, 2.8-7.1), and human immunodeficiency virus (HIV) seropositivity (OR, 39.6; 95% CI, 4.6-339.8). Community donors were also associated with recent syphilis infection (OR, 1.5; 95% CI, 1.2-1.9) compared to replacement donors.
CONCLUSION: Sexual history, including male-male sex and multiple partners, were strongly associated with recent syphilis infection, which in turn was strongly associated with HIV. Continuous and vigilant surveillance that includes assessing sexual history and other factors associated with syphilis are needed to guide blood safety policies.     

The risks and benefits of accepting men who have had sex with men as blood donors

BACKGROUND: It has been suggested that men who have had sex with men (MSM) should become eligible to donate blood if they recently abstained from male-to-male sex. STUDY DESIGN AND METHODS: The impact of a 12-month deferral policy for MSM on the risk of introducing contaminated units in the blood supply and the benefit of obtaining additional donations were estimated. Considered were the prevalence of HIV among MSM, the window period of infection, the rate of laboratory testing errors, and the occurrence of other system failures. This was compared with the risk and benefit that currently results from accepting female donors who have had sex with MSM. RESULTS: The revised policy for MSM would potentially result in one HIV-contaminated unit for every 136,000 additional donations (95% CI, 1 in 69,000 to 1 in 268,000), for an overall increase in HIV risk estimated at 8 percent. The number of donations would increase by 1.3 percent (95% CI, 0.9%-1.7%). The risk-benefit ratio of currently accepting female partners of MSM is approximately five times lower. CONCLUSION: The risk increment of accepting 12-month abstinent MSM would be very small but not zero. From a risk-benefit perspective, the current deferral policy for MSM is more efficient compared to an analogous hypothetical criterion for female partners of MSM.     

Donation deferral criteria for human immunodeficiency virus positivity among blood donors in northern Thailand

Background: The purpose of this study was to develop human immunodeficiency virus (HIV) infection donation deferral criteria for blood donors in an HIV-epidemic area of northern Thailand, where the predominant means of transmission of HIV is through heterosexual contact. Study Design and Methods: In a preliminary study, 2242 blood donors were interviewed, and their blood was tested for HIV antibodies between September 1993 and April 1994. The risk factors associated with HIV positivity were identified. Criteria to identify HIV-positive persons on the basis of a logistic equation were developed and applied to another group of 5769 prospective blood donors. Results: A multivariate analysis showed the following odds ratios (OR) for traits that were independently associated with HIV positivity: younger age (OR = 0.93 for each additional year of age), male gender (OR = 2.41), having no more than a primary school education (OR = 2.00), being in the military (OR = 1.78), being unsure of one's own blood safety (OR = 2.00), history of injecting drug use (OR = 5.36), diagnosis of syphilis or positive syphilis serologic test in the past 12 months (OR = 2.67), and genital ulcer in the past 12 months (OR = 4.56). On the basis of the model, with a limit of <10 percent loss of uninfected donors, predicted probabilities of HIV positivity alone or of markers of infection with HIV, hepatitis B virus, or Treponema pallidum were calculated. With a cutoff of 6.5-percent estimated probability of HIV infection, derived from the logistic equation, the donor deferral criteria have 33.6-percent sensitivity and 8.3-percent positive predictive value for HIV positivity and 15.5-percent sensitivity and 18.4-percent positive predictive value for markers of infection with one of the three pathogens. Conclusion: The proposed donor deferral system provides a more flexible, sensitive, and predictive tool for averting donation by those who, though HIV antibody-negative, are at a higher risk of being infected with HIV.     

Comparison of demographic and donation profiles and transfusion-transmissible disease markers and risk rates in previously transfused and nontransfused blood donors

BACKGROUND: Increasing concern about transfusion transmission of variant Creutzfeldt-Jakob disease has resulted in indefinite deferral of transfused donors in France and the UK. Little is known, however, about the impact of indefinite deferral of transfused donors on blood safety and availability in the US. STUDY DESIGN AND METHODS: Data were collected on allogeneic donations at five US blood centers during 1991 through 2000. Donation characteristics, prevalence, and incidence of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) were compared between transfused and nontransfused donors. Unreported deferrable risk (UDR) and reasons to donate were evaluated with data from a mail survey. RESULTS: Transfusion history was reported by 4.2 percent of donors. Prevalence and incidence of HIV and HBV were comparable between transfused and nontransfused donors. Although HCV incidence was similar in both groups, HCV prevalence was nearly three times higher in transfused than in nontransfused first-time donors. UDR and reasons to donate were similar in the two groups, except transfused donors were less likely to donate for screening test results (odds ratio, 0.5; 95% confidence interval, 0.3-0.8). CONCLUSION: Transfused and nontransfused donors had similar viral incidence and comparable UDR, suggesting that indefinite deferral of transfused donors would unlikely improve blood safety. Until more is known about the prevalence and transfusion transmissibility of emerging agents, indefinite deferral of previously transfused donors in the US does not appear warranted.     

A study of criteria for blood donor deferral

Donor deferral rates in regional blood centers vary from 5 to 24 per cent, reducing by more than 1,250,000 the number of units of volunteer blood available for transfusion in the nation each year. Those criteria for donor deferral which are intended to exclude donors likely to suffer a "donor reaction" are based partially on untested hypotheses and tradition. In a six-month prospective study, we adopted more liberal criteria for donor acceptance. During this period, donor reaction rates did not increase, and the deferral rate fell from 10 to 7 per cent. Our findings suggest that less restrictive criteria can be used for donor selection without compromising donor safety. If all blood centers reduced their deferral rates to 7 per cent, the nation's blood supply would be increased by more than 500,000 units annually.     

Modeling red cell procurement with both double-red-cell and whole-blood collection and the impact of European travel deferral on units available for transfusion

BACKGROUND: In 1997 the FDA approved the first double-red-blood-cell (2RBC) collection device. Soon after, travel deferral for variant Creutzfeldt-Jakob disease (vCJD) risk was adopted. To show the importance of including 2RBCs in predictive models of the blood supply, an existing whole-blood (WB) model was updated to include 2RBC collection and then run to simulate the effect of vCJD deferral on total RBC availability. STUDY DESIGN AND METHODS: The model simulates donation of allogeneic WB and 2RBCs, with donors stratified into eight age and sex groups. The model was updated with 2003 donation and economic data from 16 blood centers. RESULTS: The distribution of donations by demographic group differed both within and between WB and 2RBCs. Overall, 2RBC donation made up 24 percent of transfusable RBC units, at a lower per-unit acquisition cost from both the blood bank and the societal perspectives. Component fees from hospitals would alter this interpretation. The model predicts that vCJD travel deferral led to a 3.3 percent (95% confidence interval [CI], 2.3-4.1) decrease in the total number of RBC units, which was more than offset by 2RBC collection, resulting in a 10.4 percent (95% CI, 9.8%-11.1%) net increase in RBC units. Modeled 2RBC results match operational records, whereas vCJD deferral is overestimated. CONCLUSION: Shifting to 2RBC collection led to a substantial gain in available RBCs: even with policies that adversely affect the quantity of RBCs in the supply, 2RBC collection results in a net gain. The economics of 2RBC collection are not as clear, however.     

Estimating blood donor loss due to the variant CJD travel deferral

BACKGROUND: The FDA recommended new travel deferrals in May 2002 to prevent the potential transmission of variant CJD (vCJD). The predicted impact of such deferrals on the blood supply was controversial. STUDY DESIGN AND METHODS: We distributed anonymous, self-administered questionnaires to donors over 2 weeks in April 2002. Two thousand surveys were allocated to each of five geographic groupings of blood centers in the western and central US. Results were analyzed with chi-squared tests and logistic regression. RESULTS: Of 9800 surveys, 7405 (76%) were returned and analyzed. Overall, 257 (3.47%; 95% CI, 3.05-3.89) donors responding to the survey met the expanded May and November 2002 FDA vCJD travel criteria for deferral. Deferral rates ranged from 1 percent or less in Northern and Southern centers, 3 to 4 percent in San Francisco, California, and Scottsdale, Arizona, to over 13 percent in El Paso, Texas (p < 0.0001). Service at a European military base was the most common reason for deferral, whereas in San Francisco most deferrals were for UK and European travel or residence. The vCJD deferral was also associated with ages 30 through 49 years and with male gender. During June through September 2002, observed deferral rates were 1.6 percent at the same centers. CONCLUSIONS: Predicted deferrals due the new vCJD travel criteria depend upon the number of military donors at a blood center, as well as on the age and gender of donors. Actual deferrals were lower than predicted by an anonymous survey.     

Risk factors for human immunodeficiency virus infection among blood donors in Sao Paulo, Brazil, and their relevance to current donor deferral criteria

BACKGROUND: The objective of this study was to investigate risk factors of human immunodeficiency virus (HIV)-seropositive blood donors in Brazil and to determine if current donor deferral criteria are appropriate. STUDY DESIGN AND METHODS: Demographic and behavioral data among cases with confirmed HIV seropositivity (n = 272) were compared with those who had a false-positive serology (n = 468) between January 1999 and December 2003 in a case-control analysis with logistic regression. RESULTS: Risk factors that should have resulted in predonation deferral were reported by 48.9 percent of HIV-positive and 9.4 percent of false-positive donors. In multivariate analysis, male cases were significantly more likely to report male-male sex (adjusted odds ratio [AOR], 26.2; 95% confidence interval [CI], 7.8-87.4), a previous sexually transmitted disease diagnosis (AOR, 3.2; 95% CI, 1.5-6.9), exchanging money for sex (AOR, 2.1; 95% CI, 1.0-4.2), and at least two partners in the past 12 months (AOR, 2.3; 95% CI, 1.4-3.6). HIV-positive male donors were also more likely to be reactive for the presence of hepatitis C virus antibody (AOR, 4.0; 95% CI, 1.3-12.0) and hepatitis B virus core antibody (AOR, 3.8; 95% CI, 1.9-7.7). Female cases were more likely to report an intravenous drug user partner (AOR, 12.4; 95% CI, 1.3-120.2), a sexual partner with multiple sex partners or who had a history of sex with a sex worker (AOR, 13.0; 95% CI, 2.7-63.2), and at least two partners in the past 12 months (AOR, 2.2; 95% CI, 1.0-5.3). CONCLUSION: A substantial number of HIV-infected donors reported a risk factor that could have been identified in the predonation screening. Male-male sexual behavior was still the strongest determinant of HIV status in the studied population.     

The potential impact of selective donor deferrals based on estimated blood volume on vasovagal reactions and donor deferral rates

BACKGROUND: Whole blood donation in the United States is restricted in volume to 10.5 mL/kg or less in an effort to prevent hypovolemic reactions, but still may exceed more than 15% of a donor's estimated blood volume (EBV). We analyzed the association of EBV with prefaint and systemic vasovagal reactions (SVRs) among whole blood donors and the potential impact of an EBV‐based deferral policy. STUDY DESIGN AND METHODS: Independent predictors for prefaint reactions and SVRs were assessed by multivariate logistic regression analysis on 591,177 unique donors participating in the Retrovirus Epidemiology Donor Study‐II study. RESULTS: Young age (16 years old odds ratio [OR], 3.70; 95% confidence interval [CI], 2.78‐4.94), low EBV (<3.5 L OR, 3.30; 95% CI, 2.57‐4.23), and first‐time donation status (OR, 2.33; 95% CI, 2.03‐2.67) were the strongest predictors for SVRs, with similar trends seen for prefaint reactions. Sex, height, race, blood center, and donation site were weakly associated predictors. A total of 5.6% of all donors had an EBV of less than 3.5 L and experienced 12.5% of all prefaint reactions and 14.5% of SVRs. The highest reaction rates were seen in donors less than 23 years old with an EBV of less than 3.5 L who comprised 2.7% of all donors, who were mostly female (99.9%), and who experienced 8.8% of prefaint reactions and 11.0% of SVRs. CONCLUSION: Young age, low EBV, and first‐time donation status are the major correlates of prefaint reactions and SVRs, suggesting that high school and college donors are at particular risk. Deferral of donors with low EBV who are less than 23 years old may offer a rational approach to protecting donors at greater risk of reactions without jeopardizing the adequacy of the blood supply.     

Estimate of the residual risk of transfusion-transmitted human immunodeficiency virus infection in sub-Saharan Africa: a multinational collaborative study

BACKGROUND: Sub‐Saharan Africa remains the epicenter of the human immunodeficiency virus (HIV) pandemic. However, there is a lack of multicenter data on the risk of transfusion‐transmitted HIV from blood centers in sub‐Saharan Africa. STUDY DESIGN AND METHODS: The incidence of HIV infections in the blood donations collected in the main blood banks of five countries (Burkina Faso, Congo, Ivory Coast, Mali, and Senegal) was determined to estimate the current transfusion risk of HIV infection using the incidence rate/window period model. RESULTS: The risk of transfusion‐transmitted HIV infections associated with the window period varied from 1 in 90,200 donations (Senegal) to 1 in 25,600 (Congo). Considering the five participating blood centers as a whole, the incidence rate of HIV‐positive donors per 100,000 person‐years was 56.6 (95% confidence interval [CI], 47.1‐67.9); the residual risk (RR) was 34.1 (95% CI, 7.8‐70.7) per 1 million donations, which represents 1 in 29,000 donations (95% CI, 1/128,000‐1/14,000). CONCLUSION: RR estimates varied according to the country. This is potentially due to a lower incidence of HIV infection in the general population or to a more efficient selection of blood donors in the countries with the lowest risk. The estimates of the transfusion risk of HIV infection in each country are important, both to assess the impact of current preventative strategies and to contribute data to policy decisions to reinforce transfusion safety.     

Seroepidemiology of Toxoplasma gondii in blood donors in Portugal

Infection with the protozoan parasite Toxoplasma gondii is prevalent in animals and humans worldwide. The present study aimed to evaluate the prevalence of antibodies to T. gondii and associated risk factors among blood donors in Portugal. Serum samples were tested for the presence of anti-T. gondii immunoglobulin (Ig) G by a modified agglutination test (MAT). A written standardized questionnaire was used to collect sociodemographic and behavioural data from the blood donors. Out of 520 participants (median age: 39.5 years; interquartile range: 29.0–47.0), who attended blood collection sessions promoted by the Portuguese Institute for Blood and Transplantation (IPST), 198 (38.1%) were positive for anti-T. gondii IgG (95% confidence interval [CI]: 33.9–42.4%). Multiple logistic regression analysis revealed that ages of 46–55 years (odds ratio [OR] = 6.72; 95% CI = 3.40–13.28), and of 56−65 years (OR = 4.34; 95% CI = 1.73–10.86), having a lower education level (OR = 2.55; 95% CI = 1.45–4.49), living in the North (OR = 2.14; 95% CI = 1.25–3.65) and in the Centre regions (OR = 2.54; 95% CI = 1.36–4.76) of Portugal, and drinking water from untreated sources (OR = 2.46; 95% CI = 1.12–5.39) were risk factors for seropositivity to T. gondii. This study provides the first data on the seroprevalence of T. gondii in blood donors in Portugal, as well insights to sociodemographic and behavioural risk factors as the basis for future prevention programs.     

No evidence of a significantly increased risk of transfusion‐transmitted human immunodeficiency virus infection in Australia subsequent to implementing a 12‐month deferral for men who have had sex with men (CME)

BACKGROUND: Male‐to‐male sex is the predominant route of human immunodeficiency virus (HIV) transmission in Australia and since the early 1980s blood services in Australia have deferred donors for this practice for at least 5 years. This retrospective analysis assesses the impact on HIV prevalence of implementing an abridged 12‐month deferral for male‐to‐male sex. STUDY DESIGN AND METHODS: The prevalence of HIV among blood donors for 5‐year periods before (Period 1) and after (Period 2) implementing the revised 12‐month deferral was compared. Using deidentified data from postdonation interviews with HIV‐positive donors the proportion disclosing male‐to‐male sex as a risk factor was compared for the two periods. RESULTS: Twenty‐four HIV‐positive donations were identified among 4,025,571 donations in Period 1 compared with 24 among 4,964,628 donations in Period 2 (p = 0.468). The proportion of HIV‐positive donors with male‐to‐male sex as a risk factor in Period 1 was 2 in 15 (13.3%), which was not significantly different from the proportion in Period 2, 5 in 16 (31.25%; p = 0.22). All five men who have sex with men risk HIV infections during Period 2 were from donors whose risk was within the 12‐month criterion for acceptability, who would have been deferred had they provided a complete history. CONCLUSIONS: We found no evidence that the implementation of the 12‐month deferral for male‐to‐male sex resulted in an increased recipient risk for HIV in Australia. The risk of noncompliance to the revised deferral rather than its duration appears to be the most important modifier of overall risk.     

Behavioral and infectious disease risks in young blood donors: implications for recruitment

BACKGROUND: Recruitment of young donors is critical to expand the donor base and sustain the blood supply. Nevertheless, there is concern that younger blood donors may have a higher risk profile than their older counterparts. STUDY DESIGN AND METHODS: The prevalence of behavioral risks associated with transfusion-transmissible viral infections and the incidence of viral markers were compared between younger and older donors. Behavioral risks included unreported deferrable risks (UDRs) and HIV test seeking estimated from anonymous donor surveys administered in 1993 and 1998. The incidence of HIV, HCV, or HBV was estimated from donors giving at five US blood centers between 1996 and 2000. RESULTS: Donors younger than 25 years of age were significantly more likely to report a UDR or HIV test seeking than those 25 years or older. ORs comparing donors 18 to 19 and 20 to 24 years of age to those 25 years or older were 2.0 (95% CI, 1.5-2.6) and 1.5 (95% CI, 1.2-1.9) for UDR and 4.5 (95% CI, 3.0-6.9) and 5.5 (95% CI, 4.2-7.1) for test seeking, respectively. Although incidence estimates did not significantly differ between age groups, HIV incidence appeared to be highest in 18- to 19-year-old donors, whereas HBV incidence was highest in 20- to 24-year-old donors. CONCLUSIONS: Donors younger than 25 years of age appeared to have a higher behavioral risk profile than older donors. The message not to donate when a behavioral risk is present or for obtaining HIV tests needs to be reinforced in younger donors.     

The microbiologic safety of umbilical cord blood transfusion for children with severe anemia in Mombasa, Kenya

BACKGROUND: Severe anemia requiring blood transfusion is common in hospitalized young children in sub‐Saharan Africa but blood is often in short supply. Umbilical cord blood may be a useful source of blood if microbiologic safety concerns can be addressed. STUDY DESIGN AND METHODS: Cord blood, donated on the labor ward at the provincial hospital in Mombasa, was cultured soon after collection (screening culture) and after a period of storage (poststorage culture). Conventional blood transfused to children at the hospital was cultured only at the time of issue (poststorage culture). Maternal sera (cord blood) and conventional blood donations were also screened for transfusion‐transmitted infection. RESULTS: At poststorage culture, the overall contamination rate of cord blood was one‐third that of conventional blood (13/449 vs. 38/434; odds ratio [OR], 0.31; 95% confidence interval [CI], 0.15‐0.61) and for bacteria of high pathogenic potential it was half that of conventional blood (4/449 vs. 7/434; OR, 0.55; 95% CI, 0.12‐2.18). Screening cultures were positive in 50% (2/4) of cord blood packs where an organism of high pathogenic potential was isolated at poststorage culture. Cord blood donors had a lower seroreactivity than conventional donors for human immunodeficiency virus (OR, 0.63; 95% CI, 0.29‐1.18), hepatitis B virus (OR, 0.32; 95% CI, 0.16‐0.59), and hepatitis C virus (OR, 0.20; 95% CI, 0.24‐0.76). For syphilis, initial seroreactivity in cord blood donors was 3.8% compared to 1.8% in conventional blood donors (OR, 2.10; 95% CI, 1.15‐3.60) but was 0.5% after retesting. CONCLUSION: With respect to bacterial contamination and seroreactivity for transfusion‐transmitted infection, the safety of cord blood in Mombasa compares favorably with conventional blood. Clinical trials of cord blood transfusion are justified.     

Epidemiologic and laboratory findings from 3 years of testing United States blood donors for Trypanosoma cruzi

BACKGROUND: At most blood centers in the United States routine testing of donations for Trypanosoma cruzi using an enzyme‐linked immunosorbent assay (ELISA) is followed by supplemental testing by radioimmunoprecipitation assay (RIPA). The objective of this study was to report the results of routine testing and risk factor data from allogeneic blood donors. STUDY DESIGN AND METHODS: T. cruzi testing data from January 2007 through December 2009 were analyzed, and risk factor interviews and follow‐up studies were conducted on seroreactive donors. Prevalences of confirmed infection and risk factors associated with infection were assessed using logistic and multivariable logistic regression. RESULTS: Of 2,940,491 allogeneic donations from 1,183,076 donors, 305 (0.01% per donation tested and 0.026% per blood donor) were repeat reactive (RR) and 89 of those were confirmed positive by RIPA, yielding an overall seroprevalence of 1 per 33,039 donations and 1 per 13,292 donors. Country of birth and US blood center location differences in the seroprevalence of T. cruzi were evident. The odds of confirmed infection were highest if the donor reported having been bitten by the reduviid (kissing) bug (odds ratio [OR], 76.1; 95% confidence interval [CI], 11.1‐3173) followed by having lived in a rural area of Latin America (OR, 38.6; 95% CI, 15.1‐102.5). In multivariable analyses, having spent 3 months or more in Mexico or Central and/or South America was associated with the highest odds of RIPA‐confirmed infection (OR, 8.5; 95% CI, 2.7‐26.5). Polymerase chain reaction (PCR) testing of ELISA RR donors exhibited low sensitivity (1/22 [4%] RIPA‐confirmed donors was PCR positive). CONCLUSION: Risk factors for confirmed infection in US blood donors are consistent with the known epidemiology of Chagas disease. Blood donors or transfusions do not substantially contribute to the burden of T. cruzi infection in the United States.     

Predictive value of past and current screening tests for syphilis in blood donors: changing from a rapid plasma reagin test to an automated specific treponemal test for screening

BACKGROUND: This study evaluated the change from a rapid plasma reagin (RPR) test to an automated specific treponemal test (PK-TP) in screening for syphilis in blood donors. STUDY DESIGN AND METHODS: A cross-sectional seroprevalence analysis was performed on 4,878,215 allogeneic blood donations from 19 American Red Cross Blood Services regions from May 1993 through September 1995. Positive predictive values relative to the confirmatory fluorescent treponemal antibody absorption test (FTA-ABS) were calculated. Differences in seroprevalence were compared in RPR and PK-TP tests for 1) unconfirmed and confirmed tests, 2) first-time and repeat donors, and 3) "recent" versus "past" infections. Donation data from three additional Red Cross regions were evaluated for repeat donation patterns of blood donors who had a donation that was positive in a serologic screening test for syphilis. The value of RPR and PK-TP tests as surrogate markers for HIV infection was compared. RESULTS: Reactive rates were lower but the positive predictive values was higher for the PK-TP test than for the RPR test. Initially, donors screened by PK-TP were more likely to be confirmed as positive than were donors screened by RPR, but these rates became comparable. It is estimated that a single HIV window-period donation was removed by serologic testing for syphilis each year of this study period. CONCLUSIONS: The change to the PK-TP test resulted in a lower repeatedly reactive rate, better prediction that a confirmed-positive test for syphilis would occur in testing in the FTA-ABS, fewer donations lost, and comparable deferral rates. Because of the high rate of reactivity to serologic testing for syphilis among donors previously confirmed positive for syphilis, indefinite deferral after a confirmed-positive index donation may be warranted. Serologic testing for syphilis is ineffective as a marker of HIV-infectious window-period donations.     

Demographic characteristics and prevalence of serologic markers among blood donors who use confidential unit exclusion (CUE) in São Paulo,Brazil: implications for modification of CUE polices in Brazil

BACKGROUND: This study evaluated demographic profiles and prevalence of serologic markers among donors who used confidential unit exclusion (CUE) to assess the effectiveness of CUE and guide public policies regarding the use of CUE for enhancing safety versus jeopardizing the blood supply by dropping CUE. STUDY DESIGN AND METHODS: We conducted a cross‐sectional analysis of whole blood donations at a large public blood center in São Paulo from July 2007 through June 2009, compared demographic data, and confirmed serologic results among donors who used and who have never used CUE (CUE never). RESULTS: There were 265,550 whole blood units collected from 181,418 donors from July 2007 through June 2009. A total of 9658 (3.6%) units were discarded, 2973 (1.1%) because CUE was used at the current donation (CUE now) and 6685 (2.5%) because CUE was used in the past (CUE past). The CUE rate was highest among donors with less than 8 years of education (odds ratio [OR], 2.78; 95% confidence interval [CI], 2.51‐3.08). CUE now donations were associated with higher positive infectious disease marker rates than CUE never donations (OR, 1.41; CI, 1.13‐1.77), whereas CUE past donations were not (OR, 1.04; CI, 0.75‐1.45). CONCLUSION: The CUE process results in a high rate of unit discard. CUE use on an individual donation appears predictive of a high‐risk marker‐positive donation and, thus, appears to contribute modestly to blood safety. The policy of discarding units from donors who have previously CUE‐positive donations does not improve safety and should be discontinued.     

Human herpesvirus 8 seroprevalence and viral load in healthy adult blood donors

BACKGROUND: Human herpesvirus 8 (HHV-8) is widely suspected to be a human tumor virus because it is associated with Kaposi's sarcoma and primary effusion B cell lymphoma. Report of a case of HHV-8-positive donor blood in the US has led to concern for the safety of donor blood from HHV-8-seropositive donors. STUDY DESIGN AND METHODS: The findings of HHV-8 seroprevalence and virus load from 100 randomly selected blood donors from the Houston, Texas, area are reported. Serology with serial titration was performed using a highly sensitive indirect immunofluorescence assay to lytic and latent HHV-8 antigens. For detection of blood-borne virus, buffy-coat DNA was subjected to two ultrasensitive nested PCR-dot blot assays to HHV-8 orf26 and orf72 regions. RESULTS: At a screening titer of 1 in 10, nearly one-quarter (23%; 95% CI, 15-33) of the blood donors are HHV-8 seropositive with a geometric mean titer of 1 in 53. Seroreactivity to lytic antigens (23%) greatly exceeded that to latent antigens (5%). There was a significant association between seropositivity and older age (p < 0.02), white ethnicity (OR, 3.33; 95% CI, 1.40-7.95) and ABO blood group B (OR, 6.44; 95% CI, 2.46-16.80). No association with sex or CMV seropositivity was demonstrated. No HHV-8 viremia was detected, even though 64 percent of tested donor blood samples were EBV DNA positive. CONCLUSIONS: Despite a relatively high HHV-8 seroprevalence in this cohort of Houston area blood donors, HHV-8 DNA was not detected in any sample of donor whole blood using a highly sensitive PCR assay. Thus, at least in the southeast Texas region, large-scale screening of blood donor units for HHV-8 antibody or DNA seems unwarranted.