A brief history of improving blood safety

In 1937, Dr Bernard Fantus established the first blood bank in the United States at Cook County Hospital in Chicago. He is also credited with coining the term "blood bank" to describe a laboratory capable of preserving and storing blood. In just a few years, blood-banking spread across the United States and Europe. In 1940 the process of fractionation for breaking down plasma into albumin and gamma globulin was discovered, and these products soon were available for clinical use. World War II created an immediate demand for blood, and around this time the American Red Cross started using the vacuum bottle to collect and store donated blood. Whole blood donations were tested for ABO and Rh type, as well as syphilis. Meanwhile, the United States Government set up a nationwide program for collecting blood, and the "Plasma for Britain" program to aid the British war effort. During the war, albumin was used to treat shock, the Coombs test was discovered, and acid citrate dextrose (ACD) solution came into use to prolong shelf-life - thereby making more blood available for transfusion.

During World War II and the succeeding years, blood centers were established across the United States and other developed nations. The American Association of Blood Banks (AABB) was established in 1947, with a mission to promote safe blood-banking and improve public and professional education. Fueled by advances in medical care, like open-heart surgery and trauma care, there was steady increase in the demand for blood during the 1950s. In 1970, component therapy came into medical practice - first with red blood cells and plasma, and later with platelets and cryoprecipitated antihemophilic factor (AHF) for transfusion. Today, blood is transfused to a patient essentially only as one of the components of whole blood - i.e. red cells, platelets, or plasma - while whole blood is rarely transfused as such. This approach is beneficial in two respects: it is clinically better for the individual patient to receive only the component needed (and not be exposed to potential adverse effects of the other, unrelated component), and it also permits several patients to benefit from each unit of donated whole blood. In addition, the optimal storage conditions are different for the different blood components - red cells are refrigerated, plasma is frozen, and platelets are agitated at room temperature. Up to four different components may be derived from one unit of blood, but nowadays rarely more than three are prepared.

Giving blood is relatively painless and, in all but very rare circumstances, free of serious adverse consequences. The fluid lost is usually replaced naturally within 24 hours, but it can take up to two months to replace the lost red blood

Table 7.1 Risk of transfusion-related hepatitis B infection

Year

Risk/unit

Comment

1970

1

855

Based on CEP rate

1979

1

562

TTV study

1979

1

2809

TTV (today's tests)

1995

1

250,000

Test sensitivity

1996

1

63,000

Window

1999

1

138,700

Window, 1989 incidence

Source: Adapted from Dodd (2001), with permission.

Table 7.2 Current transfusion risks*

Agent

Point estimate

95% Confidence level

Hepatitis B Hepatitis C HTLV 1 and II

1 : 493,000 1 : 63,000 1 : 103,000 1 : 641,000

1 : 202,000-1 : 2,778,000 1 : 31,000-1 : 147,000 1 : 28,000-1 : 288,000 1 : 256,000-1 : 2,000,000

*Per unit of blood that is negative in laboratory testing. Adapted from Schreiber etal. (1996).

cells. Whole blood can be donated once every eight weeks (56 days). Multiple units of platelets can be collected as frequently as every two weeks by a procedure called platelet pheresis. Two or three units of plasma can be collected at a time by plasmapheresis, even more frequently. However, two units of red blood cells can safely be donated only once every 16 weeks, also by plasmaapheresis.

Over the past four decades there has been enormous improvement in the safety of the blood supply. From 1970 to 2000, the overall risk of acquiring a transfusion-transmitted infection in the United States dropped from one in 70,000 to one in 11.15 million units transfused. This is mirrored in the risk of acquiring specific infectious agents, like hepatitis B and C - for example, from 1970 to 1999 the risk of acquiring hepatitis B virus dropped from 1:855 to 1:138,700 units transfused (Dodd, 2001). Table 7.1 illustrates the risk of acquiring HBV between 1970 and 1999, and Table 7.2 illustrates current estimated risk of acquiring HIV, hepatitis B and C, and HTLV I and II via transfusion. Table 7.3 estimates the risk of acquiring these agents, comparing it with other life risks such as sports, accidents, and other illnesses.

Table 7.3 Risk assessment: infection from blood transfusion versus other life risks

Risk of new infection with transfusion-transmitted disease

Per unit transfused

Hepatitis B

63,000

Hepatitis C

103,000

HIV-1

676,000

HIV-2

<10,000,000,000

HIV-1, Subtype O

<167,000,000

Activity

Odds of death per person

per year

Motorcycling

50

Rock climbing

7150

Playing football/soccer

5000

Struck by auto

20,000

Influenza

5000

Leukemia

12,500

Earthquakes (in California)

588,000

Source: Reproduced from McCullough (1993), with permission from the Journal of the American Medical Association, © 1993; all rights reserved.

Source: Reproduced from McCullough (1993), with permission from the Journal of the American Medical Association, © 1993; all rights reserved.

A person is far more likely to die in a motorcycle accident or from rock climbing than from receiving a blood transfusion. Until 1999 the tests for infectivity mainly involved measuring antibody to the virus. An important recent addition to blood safety came in 1999 with Nucleic Acid Amplification Testing (NAT), which employs a new technology that specifically can detect very small amounts of the genetic materials of viruses like HCV HIV, and West Nile Virus (WNV).

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