Selection of whole-blood donors for hemoglobin testing by use of historical hemoglobin values

BACKGROUND: Usually, a predonation hemoglobin (Hb) measurement must precede blood donation. Hb values of a donor's previous donation might be used for selecting a subgroup in which predonation Hb measurements are unnecessary. STUDY DESIGN AND METHODS: Only donors with historical Hb values below 129 or 139 g per L for female and male donors, respectively, underwent venous Hb measurement before phlebotomy with an automated hematology analyzer. All other donor phlebotomies were collected without initial Hb testing. Hb values from diversion samples from 81,913 consecutive donors between May 2003 and November 2005 were subsequently analyzed as representing their present values. Donors were grouped according to interdonation intervals of less than 6, 6 to 11, 12 to 23, and 24 months or more. RESULTS: The arithmetic mean deviation between historical and present Hb values was between -0.3 and +1.8 g per L for each group (mean deviation, 5.2-6.7 g/L). Not testing selected donors spared 77.7 percent from a prephlebotomy Hb measurement and showed a specificity of 29 percent. Sensitivities for detection of donors below Hb limits (between 56% and 67% for the different subgroups) and donors with Hb values below 110 g per L (82%-88%) were at least comparable to capillary Hb screening. A total of 4.8 percent of donors were phlebotomized with values below 125 and 135 g per L, whereas only 0.016 percent of donors were bled despite Hb levels below 110 g per L. CONCLUSION: Selecting donors for a current Hb measurement based upon their last whole-blood predonation Hb value is a useful method, even after prolonged interdonation intervals.     

Seroprevalence of known and putative hepatitis markers in United States blood donors with ALT levels at least 120 IU per L

BACKGROUND: ALT testing of blood donors was initiated as a surrogate marker for non-A, non-B hepatitis. Increased sensitivity of subsequent HBV and HCV tests used for standard donor screening make any residual value of ALT testing questionable. STUDY DESIGN AND METHODS: A prospective study was conducted in 166 of 645 eligible blood donors from three American Red Cross regions whose ALT was > or =120 IU per L and whose standard donor screening tests were negative. Of these enrolled donors, 124 (75%) completed follow-up. Samples obtained from the index donation, at enrollment (1 month), and at follow-up (6 months) underwent the standard donor screening tests, as well as those for HCV RNA and HGV RNA (RT-PCR), antibodies to the virus envelope E2 protein of GB virus type C (GBV-C E2 antibody), and IgM antibody for CMV, parvovirus B19, EBV VCA, and HAV. Participants completed a brief demographic and exposure history questionnaire at follow-up. RESULTS: All study samples were negative in standard donor-screening tests. ALT levels were variable at return visits, with 80 to 86 percent <120 IU per L. No participants were positive for HCV RNA; 4 percent were positive for HGV RNA, and 10 percent were positive for GBV-C E2 antibody. Results of CMV, parvovirus B19, EBV VCA, and HAV testing were similar to published background rates. No demographic or exposure history variables had significant correlation with ALT or other testing results. CONCLUSION: These data suggest that an ALT > or =120 IU per L in blood donors with negative standard screening tests has questionable value as a surrogate marker for seronegative HBV or HCV infection. Continued ALT testing may contribute little, if anything, to the safety of blood components or plasma for further manufacture.     

Risk behavior in Norwegian blood donors

BACKGROUND: Blood banks ensure the safety of blood components by testing them for a set of known infectious agents and by careful selection of donors based on a self-administered questionnaire and an interview. The purpose of this study is to describe the risk behavior for sexually transmitted diseases in Norwegian blood donors. STUDY DESIGN AND METHODS: A survey of the sexual habits of 5,859 blood donors in the capital of Norway was performed by using anonymous questionnaires. The results were compared with a previous survey of 10,000 randomly selected Norwegian subjects aged 18 to 60 years. The response rates were 70.3 percent and 48.4 percent, respectively. RESULTS: Blood donors had considerably more education than the general population. Their general sexual behavior was similar to that of the rest of the population, although the blood donors had later sexual debut, fewer new partners per year, and a lower frequency of intercourse. In addition, homosexual experience among males was much lower in the donor group. Blood donors were less likely to engage in risk behavior for sexually transmitted diseases than were the general population. Nevertheless, 1.5 percent of the donors reported behavior that would have led to deferral had the behavior been disclosed at the predonation interview. Deferrable donors were more likely to be male and young and to have had many partners. CONCLUSION: Anonymous questionnaires reveal information that is not given at the time of blood donation.     

Accuracy of predonation Hct sampling affects donor safety, eligibility, and deferral rates

BACKGROUND: Safe blood donation depends upon reliable predonation Hct screening. Earstick (ES) capillary samples are frequently used, but they may not be accurate. STUDY DESIGN AND METHODS: Predonation ES and fingerstick (FS) and postdonation venous Hct results were compared in 1960 whole-blood and 210 apheresis donors. The validity of using postdonation venous samples to evaluate predonation ES and FS Hct was assessed in 20 whole-blood donors. The impact of Hct screening method on donor Hct deferrals was examined during periods when either ES or FS sampling was used exclusively. RESULTS: All donors were eligible to donate on the basis of a predonation capillary Hct of > or = 38 percent. In venous samples obtained immediately after donation, 36 percent of whole-blood donors had a Hct <38 percent. With correction for a decrease of approximately 2 Hct units during donation, 20 percent of these donors had a predonation Hct <38 percent. The lowest venous Hct was 23.1 percent. FS samples showed better correlation with venous Hct. Hct discrepancies were similar for apheresis donors. Hct deferrals were significantly higher with FS sampling, especially among women. CONCLUSION: Hct determinations from ES samples overestimate venous Hct. Fingerstick samples are more sensitive in detecting anemia. The accuracy of predonation Hct sampling has implications for donor safety, eligibility, and deferral rates.     

A case-controlled multicenter study of vasovagal reactions in blood donors: influence of sex, age, donation status, weight, blood pressure, and pulse

BACKGROUND: Vasovagal reactions occur in a small, but significant number of blood donors. These reactions may decrease return donation and disrupt blood collection activities. The purpose of this study was to define the contributory role of sex, age, weight, blood pressure, and pulse in vasovagal reactions with syncope in blood donors. STUDY DESIGN AND METHODS: A retrospective case-control study involved 1890 blood donors with syncope from three large United States blood centers during 1994 and 1995. Case controls and random population controls were used in a logistic regression analysis to determine the significance of individual variables to syncopal reactions. RESULTS: Female donors, young donors, first-time donors, low-weight donors, and donors with low predonation blood pressure had higher absolute donation reaction rates than other donors. When each variable was adjusted for other variables by regression analysis, age, weight, and donation status (first-time or repeat donor) were significant (p<0.0001), and sex, predonation blood pressure, and predonation pulse were not. The most important variables, in descending order, were age, weight, and donation status (first-time or repeat donor). CONCLUSIONS: Donation-related vasovagal syncopal reactions are a multifactorial process determined largely by age, weight, and first-time donor status.     

Vasovagal symptoms mediate the relationship between predonation anxiety and subsequent blood donation in female volunteers

BACKGROUND: Although not universal, a certain amount of predonation anxiety is common and not surprising among inexperienced blood donors. Variations in predonation anxiety, however, may influence the donor's experience in several respects and might be related to the likelihood of subsequent donation even among those who do not report particularly high levels of anxiety. STUDY DESIGN AND METHODS: A total of 671 inexperienced blood donors (zero or one prior donation) enrolled in a treatment study and completed questionnaires assessing anxiety before and after giving blood. Ratings of pain and blood donation-related symptoms were obtained after giving blood, as well as information from the nurses about the blood donation procedure. Follow-up information on number of additional visits to a blood collection clinic during the subsequent year was also obtained for most participants. RESULTS: Predonation anxiety was positively related to ratings of blood donation-related symptoms and chair reclining by the nurses and negatively related to the donor's rating, obtained at the end of the procedure, of the likelihood that he or she would give blood again. Women, but not men, with higher predonation anxiety were significantly less likely to return to a blood clinic in the following year. The results of mediation analyses suggest that this was due to the association between anxiety and donation-related symptoms. CONCLUSION: The results do not indicate whether or not it is feasible or useful to modify predonation anxiety, but highlight the relationships between the emotional state of inexperienced donors and several aspects of the donation experience, including subsequent donor return. Further study of the psychosocial aspects of blood donation and examination of related research (e.g., treatment of dental anxieties) may be worthwhile.     

Deferred donor care in a regional hospital blood center in Ghana

BACKGROUND: In sub-Saharan Africa, the viral marker burden in blood donor populations ranges between 10 and 30 percent. Deferred donors constitute a rare population of asymptomatic human immunodeficiency virus (HIV)- and hepatitis B virus (HBV)-infected individuals with high likelihood of long survival if cared for. Deferred donor care provides an opportunity for a public health impact on highly pathogenic infections.
STUDY DESIGN AND METHODS: Between 2004 and 2007, all candidate donors deferred before donation for reactivity of anti-HIV, hepatitis C virus antibody (anti-HCV), and hepatitis B virus surface antigen (HBsAg) rapid tests were informed and referred to a donor care program consisting of test confirmation, information, counseling, and potential referral for follow-up and therapy. Dedicated trained nurses supervised the program including alanine aminotransferase (ALT) level testing to identify liver disease.
RESULTS: In a 4-year period 51,100 donors were screened and 5778, 1578, and 227 candidate donors were deferred for reactivity to HBV, HIV, or HCV serologic markers, respectively. The rates of entry into the donor care program were 48, 14.3, and 22 percent of deferred donors, respectively. A total of 83 of 210 HBsAg-positive donors with elevated ALT levels were referred and 66 received antiviral treatment. A total of 89 of 516 confirmed anti-HIV–positive donors were referred to the hospital acquired immune deficiency syndrome clinic for follow-up.
CONCLUSIONS: With little additional expense, the deferred donor care program identified asymptomatic infections with high odds of benefiting from monitoring and therapy. In the local circumstances, this public health–limited but definite impact was permitted by the rapid-test predonation screening, and this impact could be increased if more resources were available.     

Predonation hydration and applied muscle tension combine to reduce presyncopal reactions to blood donation

BACKGROUND: A randomized controlled trial was conducted to test the effects of hydration and applied muscle tensing on presyncopal reactions to blood donation. Both interventions are designed to prevent the decreases in blood pressure that can contribute to such reactions, but due to the distinct physiologic mechanisms underlying their pressor responses it was hypothesized that a combined intervention would yield the greatest benefit. STUDY DESIGN AND METHODS: Before blood donation, first‐ and second‐time blood donors (mean age, 20.2 years; SD, 4.9) were randomly assigned to 1) standard donation, 2) placebo (leg exercise before venipuncture), 3) predonation water, or 4) predonation water and leg exercise during donation. RESULTS: Main effects of group were observed for phlebotomist classification of vasovagal reactions (χ²(3) = 8.38, p < 0.05) and donor reports of presyncopal reactions (χ²(3) = 13.16, p < 0.01). Follow‐up analyses of phlebotomist classifications revealed fewer reactions in the predonation water and predonation water and leg exercise groups relative to placebo but not standard donation. Follow‐up analyses of self‐reported reactions revealed that women, but not men, had lower scores in both the predonation water and the predonation water and leg exercise groups relative to both placebo and standard donation. CONCLUSIONS: Predonation hydration and a combination of hydration and leg exercise may help attenuate presyncopal reactions in relatively novice donors, although future studies with larger samples are required to confirm this effect.     

Donor return after temporary deferral

BACKGROUND: The consequences of temporary predonation deferral are unsatisfactorily understood. Studies have found that deferral negatively impacts future donor return. However, the applicability of these findings across centers has not been established. STUDY DESIGN AND METHODS: Using a cohort design, presenting donors with a temporary deferral in 2006 to 2008 in one of six categories (low hematocrit [Hct], blood pressure or pulse, feeling unwell, malaria travel, tattoos or piercing and related exposures, or could not wait or second thoughts) were passively followed for up to a 3‐year period for the time to first return after deferral expiration at six US blood centers. Time‐to‐event methods were used to assess return. We also analyzed which donor characteristics were associated with return using multivariable logistic regression. RESULTS: Of 3.9 million donor presentations, 505,623 resulted in deferral in the six categories. Low Hct was the most common deferral, had the shortest median time to return (time in days when 50% of deferred donors had returned), and had the largest cumulative proportion of donors returning. Deferrals of shorter duration had better return. Longer‐term deferrals (up to 1 year in length) had the lowest cumulative return proportion, which did not exceed 50%. Return was associated with previously identified factors such as repeat donor status, older age, and higher educational attainment regardless of the type of deferral. In addition, return was associated with having been born in the United States and donation at fixed sites. CONCLUSION: The category of temporary deferral influences the likelihood of future return, but the demographic and donation factors associated with return are largely consistent regardless of the deferral.     

Effects of oral donor questioning about high-risk behaviors for human immunodeficiency virus infection

The purposes of this study were 1) to compare blood donor deferrals resulting from additional, oral questions about human immunodeficiency virus risk behaviors with deferrals resulting from currently used, written screening questions; 2) to examine differences in donor deferral resulting from use of an indirect (IQ) versus direct (DQ) additional oral question format; and 3) to evaluate written survey responses of donors and staff members to the additional questions. The IQ group (n = 3050) were asked if they understood the seven ineligible-donor risk behaviors, and the DQ group (n = 4753) were asked if they had engaged in any of these behaviors. Owing to positive answers or refusal to answer the additional questions, there was an increase in donor deferrals, over the level seen with customary screening. Only 1 percent of donors indicated they would not return if the questions were asked in the future. Embarrassment was indicated by 3 percent of the IQ group and 7 percent of the DQ group; 14 to 15 percent preferred to write their answers rather than give them orally. The staff members generally felt training was adequate (IQ = 92%, DQ = 83%) and were comfortable asking the questions (IQ = 82%, DQ = 78%). Mean screening times were 5.7 minutes before the addition of the oral questions, 7.5 minutes with IQ, and 7.6 minutes with DQ. This study confirms the value of IQ and DQ formats in identifying potentially infectious donors and suggests that the DQ format may be slightly more effective.     

Donor deferral and resulting donor loss at the American Red Cross Blood Services, 2001 through 2006

BACKGROUND: A large number of blood donors are deferred each year and many of the temporarily deferred donors do not return to donate blood. This study analyzed actual deferral and return donation data from the American Red Cross to further assess the impact of donor deferral on donor availability. STUDY DESIGN AND METHODS: Voluntary blood donors who presented between 2001 and 2006 were included in this study. Deferred donors were classified into three groups according to their history of presentation during the prior 2 years: Group 1 with no prior donation or deferral, Group 2 with prior donation but no deferral, and Group 3 with prior deferral. Temporarily deferred donors in Groups 1 and 2 who did not return during the next 3 years were considered lost donors. All indefinitely deferred donors were lost donors. RESULTS: A mean of 12.8 percent of a total of 47,814,370 donor presentations between 2001 and 2006 resulted in a deferral. While majority of the deferrals were related to donor safety reasons, deferrals for recipient safety reasons accounted for 22.6 percent of deferrals or 2.9 percent of total presentations. Temporary and indefinite deferrals for recipient safety‐related reasons collectively caused an estimated loss of 647,828 donors during the 6 years. An additional 1,042,743 donors were lost due to deferrals for donor safety‐related reasons during the same period. CONCLUSIONS: The results on donor loss after deferral call attention to the impact of donor deferrals on donor availability and the need to monitor and assess the necessity and effectiveness of such deferrals.     

Bruising following blood donation, its management and the response and subsequent return rates of affected donors

A study was undertaken to determine the incidence of bruising among blood donors and to analyse their response to the management of this complication. A total of 52 510 donors were bled at 476 consecutive donor sessions held by the Brentwood Centre during a 4-month period. Of these, 344 donors (0.66%) were found to have developed bruises following venepuncture. The incidence of bruising among males was 0. 35% and that among females was 0.98%. All bruised donors were managed by the Centre nursing and medical staff. One hundred and sixty-one donors informed the Centre that they were fully satisfied with the way their bruising was managed. Of 329 bruised donors who remained in the panel, 249 (75.7%) attended subsequent blood donor sessions in response to routine invitations, showing that the majority of bruised donors continued to donate blood. This response was compared with that of a control group of donors who did not develop any complications and there was no significant difference in the return rates between the two groups.     

The persistence and significance of elevated alanine aminotransferase levels in blood donors

The level of alanine aminotransferase (ALT) in blood donors has been related to the frequency of posttransfusion hepatitis in recipients. Sixty-seven donors with elevated ALT levels were evaluated to define the duration and significance of the elevation. The ALT level remained elevated in 41 donors (61%) for a mean interval of 9 months. The ALT level was greater than the aspartate aminotransferase in all of the donors. Alcohol intake did not correlate with ALT level. Donors with persistently elevated ALT levels had a significantly higher mean percent ideal body weight (128 +/− 3.9) than donors whose ALT level became normal (116 +/− 3.1). Nine donors with elevated ALT levels for at least 6 months had needle biopsies of the liver. Seven had prominent fatty vacuolization of hepatocytes without evidence of alcoholic hepatitis. One biopsy demonstrated chronic persistent hepatitis. No other cause for the elevated ALT levels could be identified. An overweight male donor with an isolated ALT elevation may need no further investigation unless clinical evaluation suggests a source of liver injury.     

The potential impact of incentives on future blood donation behavior

BACKGROUND: It is important to assess the potential efficacy and safety of offering donation incentives as part of recruitment and retention programs. STUDY DESIGN AND METHODS: In 1995, 7489 allogeneic donors responded to an anonymous mail survey that inquired about demographics, donation history, infectious disease risks, and the potential appeal of incentives. RESULTS: The projected net effect of offering blood credits and medical testing would be to motivate, respectively, 58 percent and 46 percent of donors to return, whereas offering an item of limited value would motivate 20 percent to do so. First-time and younger donors reported more frequently than repeat or older donors that incentives would appeal to them. Donors attracted by cash were 60 percent more likely to have a risk for transfusion-transmissible infections (p = 0.03). Although not statistically significant, the odds of being an at-risk donor were higher among individuals attracted by tickets to events (OR 1.5) and extra time off work (OR 1.2). CONCLUSION: These findings suggest that offering blood credits and (though to a lesser extent) items of limited value could be safe and effective strategies for retaining donors. Although medical tests were found to have broad appeal, studies are needed to identify tests in which donors would be most interested.     

Serum alanine aminotransferase in blood donors: activity distribution and effect of phenotype

Alanine aminotransferase (ALT) phenotype and serum activities were determined in 200 random volunteer blood donors. Serum enzyme activities were not significantly affected by the ALT phenotype (p greater than 0.1). Studies on 500 random volunteer blood donors showed significant differences in serum ALT levels between male and female donors (p less than 0.001). Elevated serum ALT levels were more commonly found in male donors; the frequency of male donors with levels of 45 IU/l or higher was 2.5 percent compared with 0.9 percent in female donors. The frequency of donors with serum ALT levels of 80 IU/l or higher was 0.6 percent of the total donor population sampled.     

Controversies in transfusion medicine. Alanine aminotransferase screening of blood donors: pro

In my opinion, independent, carefully conducted scientific studies indicate that an accurate, rapid, relatively sensitive, and inexpensive laboratory test substantially reduces the major long-term risk of blood transfusion in the United States; donor ALT has emerged as one of the most effective laboratory determinants for reducing the incidence of NANB PTH. Despite its nonspecificity and limited predictive value, ALT screening may prevent up to 30 percent of cases, one-half of which would progress to chronic liver disease and then possibly to cirrhosis and hepatocellular carcinoma. Blood donors appear to understand and accept the testing rationale as a reasonable precaution. Admittedly, ALT screening is not a perfect solution. It has not been validated by prospective studies and probably never will be. Determination of the proper cutoff value remains controversial. However, the risk of PTH progresses with increasing ALT levels, so that the real issue is not whether to test, but how best to configure the test to exclude the fewest false-positive donors while detecting the most true-positive donors. It is undesirable and expensive to discard safe units of blood, but the primary responsibility of blood collectors is to ensure an adequate supply of safe components. Some still consider the ALT assay technically too demanding for routine use. However, technical concerns regarding performance and interpretation are not insurmountable, and both quality control and proficiency testing are being addressed at the national level. The assay is capable of great precision, and a system employing a national standard and single cutoff has already been described and tested with excellent results. Circumstances have changed since donor screening with ALT was widely implemented in 1986. More thorough screening and testing have eliminated many high-risk donors. Public expectations have changed as well. While it is neither reasonable nor responsible to promise the public blood transfusions without risk, neither is it prudent to propose any major change in management of the blood supply without compelling evidence that such a change will not impair transfusion safety. It is hard to defend discontinuing the ALT screen at this time, especially when the costs of retaining it are minimal and the benefits clearly greater than those of screening for HTLV-I and for Treponema pallidum (in the United States) or HIV-2 (in West Germany). A first-generation assay specific for antibody to hepatitis C will probably be available within a year.(ABSTRACT TRUNCATED AT 400 WORDS)     

How afraid are you of having blood drawn from your arm? A simple fear question predicts vasovagal reactions without causing them among high school donors

BACKGROUND: We previously demonstrated in a group of mostly experienced blood donors that fear of blood draws was a significant predictor of vasovagal reactions. Importantly, being asked about one's fear immediately before donation did not increase reaction rates. This study further evaluates the relationship between fear and reactions among high school blood donors, who are known to be at a relatively greater risk for vasovagal reactions. STUDY DESIGN AND METHODS: Immediately after completing the blood donor health screening, 17‐ and 18‐year‐old high school students were asked about their fear of having blood drawn. Based on a random selection, the fear question was administered in approximately half of the schools, resulting in a final sample of 1715 donors who did and 1692 donors who did not answer the fear question. RESULTS: Fear was a significant predictor of donor reactions and remained a significant independent predictor (along with estimated blood volume and donor sex) in a logistic regression analysis. There was no difference in the proportion of reactions observed between those who did and did not answer the predonation fear question. CONCLUSION: Consistent with previous evidence in older and more experienced blood donors, these findings indicate that assessing fear of blood draws may help to identify those who are most likely to experience vasovagal reactions among young donors without increasing the frequency of such reactions.     

Blood donor satisfaction and intention of future donation

BACKGROUND: New regulatory requirements for donor eligibility challenge blood centers to recruit and retain enough donors. This study evaluated correlations between overall satisfaction with the donation process and donor demographics and the effect of both on a donor's intent to return. STUDY DESIGN AND METHODS: An anonymous, self-administered questionnaire was given to donors at multiple sites of one blood center over a 3-week period. First-time and repeat donors were asked questions on demographic characteristics, satisfaction with the current donation process, motivation for current and future donations, and intent to return. RESULTS: More than 75 percent of donors rated the overall donation process at 9 or 10 on a scale of 10 (mean, 9.19; standard deviation, 1.09), with female, high school-educated, and first-time donors giving higher satisfaction ratings than male, college-educated, and repeat donors, respectively (all p < 0.001). Donor satisfaction was correlated with intent to return for another donation (p = 0.002). For the current donation, donors rated altruistic motivations most highly. Medical testing was the most highly rated incentive for future donations, followed by frequent donor programs and convenient donation times and locations; preferences varied by demographic subgroup. CONCLUSIONS: Blood donor satisfaction varies among demographic and donation history subgroups and is positively correlated with the intent to return for future donation. Although the primary motivation among all donors was altruism, incentives to future donation may need to be tailored according to demographic subgroups.     

Validity of testing alanine aminotransferase in refrigerated whole blood

Alanine aminotransferase (ALT) was tested in the sera and plasma of in-line segments as well as the main bags of whole blood units collected from blood donors. The purpose of this study was to evaluate the stability of enzyme activity during blood storage when the analysis of ALT is postponed over weekends or holidays. In addition, when validation of a particular result is requested, an in-line segment may be convenient for confirmatory testing. While a dilutional effect was found, the anticoagulant in the main collection bag was not shown to have affected enzyme activity. During storage the mean enzyme concentration decreased. Appropriate plasma ALT cutoffs for respective time periods during storage were calculated to compensate for downward drift. This correction prevented the use of the blood units (40% of total) that would erroneously have appeared transfusable if the serum cutoff had been used. If the Day 0 plasma cutoff was used throughout the total storage time period, 14 percent of the blood would erroneously have appeared transfusable.     

Frequent plateletpheresis does not clinically significantly decrease platelet counts in donors

BACKGROUND: In October 2005, the US Food and Drug Administration (FDA) issued draft guidance on collecting platelets (PLTs) by automated methods. The FDA proposed limiting collections to 24 components, rather than 24 procedures, annually with up to 3 components per procedure. The rationale was from literature suggesting frequent PLT collection resulted in significant declines in donor PLT counts. Additional requirements for minimal interdonation intervals were proposed. STUDY DESIGN AND METHODS: Plateletpheresis records at a regional blood center with predonation PLT counts were used to assess the impact of the restriction on PLT collections. They were reviewed to demonstrate the effects of collection frequency, number of products collected, and interdonation interval on donor PLT counts. Total protein and albumin levels were compared in a subset of 24-times-per-year PLT donors and control whole-blood donors. RESULTS: A limit of 24 components would require replacement of approximately 20 percent of the donor base to recover lost components. No clinically important decrease in PLT counts before donation was seen in donors donating multiple PLT components up to 24 times per year, regardless of interdonation interval. No frequent donor was deferred for a PLT count less than 150 x 10(9) per L. Short interdonation intervals were associated with statistically but not clinically important decreases in PLT counts. Protein levels were not distinguishable between PLT donors and controls. CONCLUSION: The proposed restrictions are not required to prevent thrombocytopenia in frequent PLT donors and would adversely impact the supply of apheresis PLTs. Protein levels are maintained in these high-frequency donors.