Biomedical subjects

Yongling Tu

Publications and source records attributed to Yongling Tu.

8 recordsLinked to original sources

PubMed2006

Convenience, the bane of our existence, and other barriers to donating.

BACKGROUND: To prevent donor loss and improve retention, it is important to understand the major deterrents to blood donation and to identify factors that can be effectively addressed by blood centers. STUDY DESIGN AND METHODS: A 30-item self-administered questionnaire was completed in 2003 by 1705 first-time and 2437 repeat US donors who had not donated in 2 to 3 years. Asian, Hispanic, black, and white first-time and repeat donors rated the importance of deterrents to donation in their decision to not return with a 1 to 5 scale. Categorical analysis of variance methods were used to compare the importance of deterrents between first-time and repeat donors of different race or ethnicity. RESULTS: Not having a convenient place to donate was most commonly cited as an important or very important reason for not returning by 32 to 42 percent of first-time and 26 to 43 percent of repeat respondents. Although bad treatment and poor staff skills were less of a barrier than convenience, they were more important for minority donors. Other factors such as physical side effects, foreign travel, or length of the process appeared less important. CONCLUSION: Inconvenience is a major barrier to donating, suggesting that mobile collections and increased hours of operation might help recapture lapsed donors. The finding that lapsed minority donors were more likely to give bad treatment and poor staff skills as important reasons to not donate is disconcerting in light of the changing donor demographics and increased efforts to recruit these donors.

Adult↗

PubMed2006

Factors influencing the decision to donate: racial and ethnic comparisons.

BACKGROUND: Understanding factors that encourage different racial and ethnic groups to donate is crucial for donor recruitment and retention. STUDY DESIGN AND METHODS: A 28-item self-administered questionnaire was completed in 2003 by 1862 Asian, 1479 black, 1641 Hispanic, and 2940 White US donors who had given whole blood within the past year. With a 1 to 5 scale, donors were asked to rate the importance of 17 factors in their last donation decision. Logistic regression was conducted to compare the odds of a factor being important or very important (score of 4 or 5) in one's decision to donate between race or ethnic groups, stratified by first-time and repeat status. RESULTS: More than 90 percent of each respondent group cited a desire, responsibility, or perceived duty to help others as an important or very important motivator. Being asked to donate at work was also an important motivator for all race and ethnic groups (56-70%). Getting the results of a health screen appealed to many (approx. 30% found it important or very important) and was most important to Black and Hispanic donors (odds ratios of 1.3-1.9 compared to White donors; p<0.003). CONCLUSION: Recruitment and retention programs should build on people's sense of social responsibility. Direct requests to donate are particularly effective motivators. Of a variety of incentives evaluated, offering more comprehensive health screens may motivate many donors, especially Black and Hispanic donors.

Adult↗

PubMed2005

Relative sensitivities of licensed nucleic acid amplification tests for detection of viremia in early human immunodeficiency virus and hepatitis C virus infection.

BACKGROUND: Screening donors for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) RNA is primarily performed on minipools (MPs) with one of two commercial nucleic acid amplification tests (NAT; Roche Molecular Systems; or Gen-Probe/Chiron). We compared these assays with respect to detection of RNA in early HIV and HCV infection. STUDY DESIGN AND METHODS: Twelve HIV plasma donor panels (116 serial samples) and 12 HCV panels (180 serial samples) were selected to optimally represent early viremia. Initial testing was performed in singlicate or triplicate on separately coded aliquots, both neat and at dilutions corresponding to MP screening (1:16 for Gen-Probe; 1:24 for Roche); 20 additional replicates were performed when discordant results were observed. Odds ratios (ORs) comparing detection of RNA by different assays were derived with logistic regression models. Differences in window-period closure and yields of assays in MP or individual-donation (ID) format were estimated. RESULTS: Differences in detection rates between Roche and Gen-Probe NAT assays were small and only observed with samples with very-low-level viremia. ORs for detecting RNA by the Gen-Probe versus the Roche assay were significant for HIV if conducted on MPs (1.8; 95% confidence interval [CI], 1.3-2.5) but not neat (1.0; 95% CI, 0.72-1.4). Odds of detecting HCV RNA were higher if the Gen-Probe assay was conducted either neat (2.3; 95% CI, 1.6-3.2) or on MPs (4.0; 95% CI, 2.8-5.8). These differences translated to <1 day window-period closure and <or=1 infection per 20 million donations. In contrast, comparisons of ID versus MP assays were highly significant for both viruses (ORs for ID vs. MP ranged from 45.3 to 93.4), with projected yields of one to two additional infections per 10 million donations. CONCLUSIONS: Differences in sensitivities of licensed NAT assays for HIV and HCV are very small and clinically insignificant, particularly when compared to differences of MP versus ID NAT screening.

Blood Banking↗

PubMed2005

Dynamics of viremia in early hepatitis C virus infection.

BACKGROUND: It is important to characterize viral dynamics in early hepatitis C virus (HCV) infection to further our understanding of viral pathogenesis and the potential for secondary transmission in acute infection through blood transfusion or other routes. STUDY DESIGN AND METHODS: Serial units given by 77 source plasma donors who had evolved from HCV RNA-negative to HCV RNA-positive by nucleic acid amplification technology (NAT) screening with 512-unit pool-NAT or were followed from RNA detection to antibody conversion were tested by individual NAT and quantitative RNA assays. RESULTS: During the ramp-up phase when exponential growth occurs, HCV viral load doubled every 10.8 hours (95% confidence interval [CI], 9.9-12.0). Intermittent viremia was observed before the ramp-up phase in 37 of 50 panels with the earliest detectable viremic bleed occurring 63 days before the estimated onset of ramp-up. The plateau phase or high-titer viremic period that occurs between ramp-up and seroconversion was estimated to last 56.3 days (95% CI, 44.8-67.8). CONCLUSIONS: Intermittent low-level HCV viremia can occur as much as 2 months before the periods of exponential increase in viral load and the high-titer plateau-phase viremia that usually precede seroconversion. Animal inoculation studies are in progress to evaluate if transfusion of low-level viremic plasma can transmit HCV infection.

Blood Donors↗

PubMed2004

Mammalian brain consumption by blood donors in the United States: brains today, deferred tomorrow?

BACKGROUND: Theoretical concerns of possible variant CJD (vCJD) transmission by transfusion have led to deferral of US donors potentially exposed to the bovine spongiform encephalopathy agent. Although the efficacy of these policies is unknown, impact on blood collections has been substantial. Under the precautionary principle, deferral of donors consuming bovine (or other mam-malian) brains, possibly contaminated with the vCJD agent, might be considered. Blood donors were surveyed to determine lifetime mammalian brain consumption. STUDY DESIGN AND METHODS: The Retrovirus Epidemiology Donor Study (REDS) conducted an anonymous mail survey of 92,581 donors from eight US blood centers. RESULTS: Responses were received from 52,650 donors (57%). Of these, 6.4 percent reported lifetime brain consumption; bovine (3.6%) and hog brains (1.7%) were the most common. Bovine brain consumption varied fourfold by center (1.7-7.0%) and was highest among male (4.5%), older (age 55+, 6.5%), foreign-born (9.2%), Asian (7.2%), and Hispanic (8.6%) donors. Among bovine brain consumers, 67 percent engaged in the practice 4 times or less, 79 percent were repeat donors, and 61 percent reported giving at least 11 donations in the past 10 years. CONCLUSION: Following the precautionary principle, further steps to reduce the theoretical vCJD risk could include deferring donors who eat bovine (or other mammalian) brains. The impact of such a policy would not be trivial, especially in areas with older, foreign-born, Asian, or Hispanic donors. Cautious implementation and periodic evaluation of deferral policies is warranted.

Adolescent↗

PubMed2003

Effect of a national disaster on blood supply and safety: the September 11 experience.

CONTEXT: An understanding of characteristics of blood donors donating in times of crisis may help predict blood supply safety and donor return patterns. OBJECTIVES: To characterize the volume of donations and prevalence of infectious disease markers in blood donated by US donors responding to the September 11, 2001, terrorist attacks, and to evaluate return rates in those who donated for the first time. DESIGN: Cross-sectional survey data from the National Heart, Lung, and Blood Institute Retrovirus Epidemiology Donor Study for 4 weeks before and 4 weeks starting with September 11, 2001, and the corresponding 8-week period in 2000. SETTING AND PARTICIPANTS: A total of 327065 volunteer blood donors making 373628 allogeneic donations at 5 large regional US blood centers. MAIN OUTCOME MEASURES: Changes in number of donations overall and by first-time and repeat status, prevalence of infectious disease markers, estimated risks of transfusion-transmitted viral infections, and first-time donor return rates. RESULTS: About 20000 allogeneic donations were collected weekly in the 4 weeks preceding September 11, whereas approximately 49 000 (2.5-fold increase) and approximately 26000 to 28000 (1.3-fold to 1.4-fold increases) donations were made per week in the first and in the second through fourth weeks starting with September 11, respectively. All demographic groups donated more than usual after the attacks, and after adjusting for seasonal and annual variation there was a 5.2-fold (95% confidence interval, 5.0-5.4) increase in the number of first-time donations vs a 1.5-fold (1.4-1.5) increase in the number of repeat donations made in the first week starting on September 11 vs the 4 weeks before. The weekly proportion of repeat donors returning after not donating for 10 or more years increased from 2% before September 11 to 6% in the first week starting with September 11. Donations confirmed positive for human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B surface antigen nearly tripled between 1 week before September 11 (0.1%) and 1 week after the attacks (0.3%), largely explained by the increase in first-time and lapsed repeat donors. Estimated viral residual risks increased slightly after the attacks (HIV, 1/1.5 million vs 1/1.8 million donations; HCV, 1/1.3 million vs 1/1.6 million; hepatitis B virus, 1/140000 vs 1/170000). First-time donor 12-month return rates for 2000 and 2001 were similar, approximately 28% (P =.37) for donors in the first week starting with September 11 (or September 12, 2000) and 30% (P =.69) for the second to fourth weeks. CONCLUSIONS: The September 11 events resulted in an influx of first-time donors without substantial increase in absolute risk of transfusion-transmissible viral infections. First-time donor return rates were equally relatively low before and after the attacks, suggesting that those donating in times of crisis have return behaviors similar to those of other first-time donors. Their relatively low return rates reinforce the need for education about the importance of donating regularly.

Blood Banks↗

PubMed2003

Lapsed donors: an untapped resource.

BACKGROUND: There is a clear need for methods to recruit and retain donors without compromising blood safety. Although prior studies report lower viral prevalence rates in repeat donors than those in first-time donors, it is unknown if this relationship holds after a lapse of several years between donations. STUDY DESIGN AND METHODS: A total of 6.4 million allogeneic donations collected at five US blood centers from 1991 through 1998 were classified by donation history (first-time vs. repeat) and by length of time between donations (lapsed interval length). The prevalence of HCV, HIV, and HBsAg was compared by donation history and lapsed interval length. The relationship between lapsed interval length and donor demographics was explored. RESULTS: Repeat donors who delayed their return for over 5 years were significantly less likely to test positive for a viral infection than were first-time donors. The likelihood of a positive test result appeared to increase steadily with lapsed interval length for HCV and HBsAg, but not for HIV. Younger, less educated, and nonwhite donors were less likely to return than others. CONCLUSIONS: Recruitment of donors who have not returned for several years could be an effective way to increase the blood supply while preserving blood safety. Understanding the relationship of donor demographics to return behavior is important for recruitment efforts.

Adult↗

PubMed2002

HIV seroconverting donors delay their return: screening test implications.

BACKGROUND: The yield of HIV p24 antigen testing implemented in March 1996 has been lower than projected. One possible explanation is that HIV seroconverting donors delay their return because of the recent practice of risk behaviors and/or signs and symptoms associated with primary infection. STUDY DESIGN AND METHODS: From a database of 6.8-million allogeneic donations collected at five U.S. blood centers from 1991 to 1997, 49 HIV, 21 HCV, 32 HTLV, and 44 HBsAg seroconverters with at least three donations were identified. A statistical method was developed to investigate whether the time between a donor's last negative donation and their positive donation was significantly longer than expected based on their previous return history. RESULTS: HIV seroconverters returned on average 42 percent later than expected (p < 0.01). Although not significant, HCV seroconverters donated on average 43 percent earlier than expected. HTLV and HBsAg seroconverters did not appear to change their donation pattern around the time of seroconversion. Sixty-three percent of the HIV seroconverters later acknowledged practicing a high-risk behavior. CONCLUSIONS: HIV seroconverters delay their return around the time of seroconversion and are thus less likely to be recently infected. Unique among HIV seroconverters, this observation provides a possible explanation for the lower than expected yield of HIV p24 antigen testing and suggests that NAT may have a similar low yield.

Blood Donors↗