Blood Donation
For a few decades , the U . S . blood donation system relied on paid donors to maintain an adequate blood supply , but in 1973 , it began operating solely on volunteer donations . Screening for disease and infection became an integral part of that system , and given the restrictions on donations , maintaining a stable blood supply has remained a constant challenge .
More than half of the nation ’ s blood supply comprises donations from people older than 40 years – and nearly 45 percent comes from people older than 50 years . Blood industry experts are concerned that younger donors are not stepping up to replace the aging donor population . The complicated conversation about who can donate , how much they can donate , and who can receive those donations may also be contributing to this scarcity .
myth : Fresh Blood Is Better Than Stored
To maximize red blood cell ( RBC ) supplies , blood banks generally dispense on a first-in , first-out basis , working off the assumption that blood stored up to 42 days ( per U . S . Food and Drug Administration [ FDA ] regulations ) will degrade to some extent , but that blood stored for this long is not inherently harmful .
Because blood undergoes several morphologic , biochemical , and physiologic changes over time , some people worry that old blood may lose its efficacy or be deleterious to recipients .
However , according to recent research , the freshversus-stored debate is getting stale .
When ASH Clinical News took a deeper look at this issue in February 2016 (“ Bad Blood : Is the Debate Over Stored Red Blood Cells Still Relevant ?”), experts agreed on two key points . First , findings from major “ fresh versus old ” blood trials such as ABLE , RECESS , TOTAL , and ARIPI have advanced the hematology community ’ s understanding of the issue , with each trial demonstrating that stored blood doesn ’ t affect clinical outcomes . Second , the community lacks a universal definition of what constitutes “ fresh ” and “ old ” RBC units , and a standard definition may not even be worth pursuing . 3
Results from the 2016 INFORM ( Informing Fresh versus Old Red Cell Management ) study demonstrated that in-hospital mortality did not differ between patients who received RBC transfusions stored for shorter periods and those who received RBCs stored long-term . 4
“ The results of the INFORM trial should reassure physicians that the routine use of fresher blood for hospitalized adults that require RBC transfusion is not justified ,” lead author Nancy M . Heddle , MSc , an associate professor of pathology and molecular medicine at McMaster University in Ontario , told ASH Clinical News .
While an editorial accompanying the publication of the INFORM results echoed Prof . Heddle ’ s sentiments , the hematology community expressed great concern with this interpretation of the findings in multiple letters to the editor published in the New England Journal of Medicine . 5
Stored RBCs , correspondents argued , undergo “ reversible and irreversible lesions ” that may affect safety and quality of the products , and the INFORM trial design did not address whether storage length and age of blood matters for outcomes other than death .
More recent studies may offer more clarity as to whether “ fresher is better ” is simply a myth or a mandate . In the international TRANSFUSE ( Standard Issue Transfusion Versus Fresher Red Blood Cell Use in Intensive Care ) trial of nearly 5,000 patients , there were no significant differences in 90-day mortality among people who received “ fresh ” blood ( stored for an average of 11.8 days ) or older blood ( stored for an average of 22.4 days ). 6
myth : Moms Can ’ t Donate
Obviously , men and women are biologically different , including differences in blood composition , such as : 7
• erythrocytes by volume : 45 % average in men and 42 % in women
• leukocytes and platelets by volume : 0.4-0.5 % in men and 0.2-0.4 % in women
• plasma by volume : 54 % in men and 57 % in women
Two categories in the Red Cross ’ s blood-donation eligibility criteria address sex differences between donors . One is “ Birth Control ,” stating that “ Women on oral contraceptives or using other forms of birth control are eligible to donate .” 8
The second concerns hemoglobin levels ; normal hemoglobin levels for healthy men range between 13.5 and 17.5 g / dL and 12.0 and 15.5 g / dL for healthy women . In 2016 , the FDA increased the minimum acceptable hemoglobin level for male blood and platelet donors from 12.5 g / dL to 13.0 g / dL , but even African-American men and women , who sometimes have slightly lower hemoglobin levels , can donate according to the Red Cross .
Eligible women are also required to wait at least six weeks postpartum before blood donation , but as long as the blood groups match and donors meet certain other health criteria ( age , weight , general good health ), sex isn ’ t necessarily part of the equation .
A recent study published in JAMA raised questions about whether it should be . 9 In the 31,000- participant study , led by Rutger A . Middelburg , PhD , of the Center for Clinical Transfusion Research , Sanquin Research in Leiden , the Netherlands , found that men who received RBC transfusions from women who had ever been pregnant were 13 percent more likely to die during a median of 245 days of follow-up , compared with men who received blood transfusions from male donors . 9
Men who received blood transfusions from women who had never been pregnant did not have an increased mortality risk , and neither did women who received blood donations from women who had been pregnant or from male donors .
The authors cautioned that the findings from the retrospective study were “ tentative ” and required further validation .
Two experts agreed , noting that the results were “ provocative ,” but shouldn ’ t signal a change in blood donor selection criteria . Ritchard G . Cable , MD , of the American Red Cross Blood Services , and Gustaf Edgren , MD , PhD , of the Department of Hematology at the Karolinska University Hospital in
“ The blood supply would be inadequate if women who had been pregnant were excluded from donating . Blood is more important than no blood in many situations .”
— ANDRA H . JAMES , MD , MPH
Stockholm , Sweden , pointed out that “ because RBC units from female donors contain about 8 percent less hemoglobin than those from male donors , patients who receive RBC units from female donors may require additional transfusions , [ which ] may bias the mortality estimates .” 10
They also highlighted that mortality differences seemed to increase a year or more after the transfusion , and the observed findings could be related to “ an immunologic mechanism based on maternal immunization to paternal antigens ” and not necessarily related to differences in donor RBCs or iron physiology .
“ The risk was very small , at 1.13 [ a 13 % higher risk ],” stressed Andra H . James , MD , MPH , a maternal-fetal medicine specialist at Duke University Health System in Durham , North Carolina , and an expert speaking on behalf of the Society of Maternal and Fetal Medicine . “ The mechanisms are interesting , but as the authors point out , the blood supply would be inadequate if women who had been pregnant were excluded from donating . Blood is more important than no blood in many situations .”
Another issue associated with female blood , and particularly donations from those who have been pregnant , is transfusion-related acute lung injury ( TRALI ), a complication most commonly caused by white blood cell antibodies present in the plasma component of blood products . When transfused , these antibodies can activate granulocytes , causing plasma to leak into the lungs , and leading to acute pulmonary edema .
“ We ’ ve known for years that blood from women is more likely to result in TRALI , an immediate allergic reaction ,” Dr . James explained . “ The JAMA study suggests that there are some long-term consequences unrelated to that allergic type response .”
As for what the results may mean for pregnant women who require blood transfusions , including patients with postpartum hemorrhage and associated bleeding disorders , she stated that the results of this study will not “ change anything about the nature of the blood that a pregnant woman should receive . There are general precautions that can be taken when pregnant women receive a transfusion , such as use of leukocyte-reduced or cytomegalovirusseronegative components , but that doesn ’ t have anything to do with the data provided in this article .” 11
66 ASH Clinical News January 2018