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Blood Collection

By Ravindra Sarode, MD, Professor of Pathology, Director of Transfusion Medicine and Hemostasis, and Chief of Pathology and Medical Director of Clinical Laboratory Services, The University of Texas Southwestern Medical Center

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More than 25 million units of blood components are transfused yearly in the US, from about 9 million volunteer donors. Although transfusion is probably safer than ever, risk (and the public’s perception of risk) mandates informed consent whenever practical.

In the US, the collection, storage, and transport of blood and its components are standardized and regulated by the FDA, the AABB (formerly known as the American Association of Blood Banks), and sometimes by state or local health authorities. Donor screening includes an extensive questionnaire and health interview; measurement of temperature, heart rate, and blood pressure; and Hb determination. Some potential donors are deferred either temporarily or permanently (see Table: Some Reasons for Blood Donation Deferral or Denial). Criteria for deferral protect prospective donors from possible ill effects of donation and recipients from disease.

Whole blood donations are limited to once every 56 days, whereas apheresis RBC donations (donations of twice the usual amount of RBCs in one sitting) are limited to once every 112 days. Apheresis platelet donations are limited to once every 72 h with a maximum of 24/yr. With rare exceptions, blood donors are unpaid. (See also the American Red Cross for information regarding donor eligibility.)

Some Reasons for Blood Donation Deferral or Denial


Donation Outcome


AIDS or participation in certain high-risk activities


Includes any positive test for HIV, ever

High-risk activity includes

  • IV drug use (ever)

  • Engaged in sex for compensation (ever)

Activities that increase risk of HIV infection


The FDA has changed recommendations for certain high-risk activities from denial to deferral for 12 mo from last such activity. Activities include

  • Men who have sex with men (MSM) and women who have sex with MSM

  • Sexual contact with a person who ever had a positive HIV test, ever engaged in sex for compensation, or ever used IV drugs



Donation permitted after anemia resolves

Bovine insulin use (because of risk of variant Creutzfeldt-Jacob disease)


People who have used bovine insulin since 1980: Ineligible to donate



Some people with mild, treatable forms (eg, small skin cancers): Possibly able to donate

Congenital bleeding disorder


Drugs (selected)


Waiting period depends on drug:

  • Finasteride: Defer for 1 mo after last dose

  • Isotretinoin: Defer for 1 mo after last dose

  • Dutasteride: Defer for 6 mo after last dose

  • Acitretin: Defer for 3 yr after last dose

  • Etretinate: Defer indefinitely

Exposure to hepatitis


Wait 12 mo after possible exposure



Ineligible to donate if ever diagnosed with viral hepatitis



Defer donation until BP is controlled

Malaria or exposure to malaria


Wait 3 yr after treatment for malaria or living in an area in which malaria is endemic; wait 12 mo after visit to an area in which malaria is endemic

Military personnel residing on US bases in Europe at risk for variant Creutzfeldt-Jacob disease


UK, Germany, Belgium, Netherlands: 6 mo between 1980 and 1990

Elsewhere in Europe: 6 mo between 1980 and 1996



Wait 6 wk after giving birth

Severe asthma


Severe heart disease


Stay in UK or Europe for people at risk of variant Creutzfeldt-Jacob disease


UK: Cumulative stay of > 3 mo between 1980 and 1996

Europe (except France): Cumulative stay of 5 yr since 1980

France: Cumulative stay of > 5 yr since 1980



Wait 12 mo

Transfusion that can increase risk of variant Creutzfeldt-Jacob disease


Wait 12 mo


Recipients of any blood product since 1980 in the UK

Vaccinations (selected)


Waiting period depends on vaccination:

  • Toxoids or synthetic or killed viral, bacterial, or rickettsial vaccines* in symptom-free and afebrile donors: No deferral

  • Measles, mumps, polio (Sabin), or typhoid (oral) vaccines: Defer for 2 wk

  • Rubella or varicella vaccines: Defer for 4 wk

Zika virus infection


For recent Zika virus infection, the US FDA recommends a 120-day deferral from resolution of symptoms or the last positive test, whichever is longer

The FDA no longer recommends screening donors for risk factors; instead, all donor blood is to be tested for Zika

*These vaccines include anthrax, cholera, diphtheria, hepatitis A, hepatitis B, influenza, Lyme disease, paratyphoid, pertussis, plague, pneumococcal polysaccharide, polio (Salk), Rocky Mountain spotted fever, tetanus, and typhoid injection.

Recipients of other live-attenuated viral or bacterial vaccines may be deferred 2 or 4 wk, depending on the vaccine.

Reflects FDA Dec 2015 Guidance document: Revised Recommendations for Reducing the Risk of Human Immunodeficiency Virus Transmission by Blood and Blood Products.

UK = United Kingdom.

In standard blood donation, about 450 mL of whole blood is collected in a plastic bag containing an anticoagulant preservative. Whole blood or packed RBCs preserved with citrate-phosphate-dextrose-adenine may be stored for 35 days. Packed RBCs may be stored for 42 days if an adenine-dextrose-saline solution is added.

Autologous donation, which is use of the patient’s own blood, is less preferred as a method of transfusion. When done before elective surgery, up to 3 or 4 units of whole blood or packed RBCs are collected in the 2 to 3 wk preceding surgery. The patient is then given iron supplements. Such elective autologous donation may be considered when matched blood is difficult to obtain because the patient has made antibodies to red cell antigens or has a rare blood type. Special blood salvage procedures are also available for collecting and autotransfusing blood shed after trauma and during surgery.

Pretransfusion Testing

Donor blood testing includes

Compatibility testing tests the recipient’s RBCs for antigens A, B, and Rh0(D); screens the recipient’s plasma for antibodies against other RBC antigens; and includes a cross-match to ensure that the recipient’s plasma is compatible with antigens on donor RBCs. Compatibility testing is done before a transfusion; however, in an emergency, testing is done after releasing blood from the blood bank. It can also help in diagnosing transfusion reactions.

The addition of a cross-match to ABO/Rh typing and antibody screening increases detection of incompatibility by only 0.01%. Therefore, many hospitals do computerized electronic cross-matches rather than physical cross-matches in a test tube in patients who have negative antibody screening. If the recipient has a clinically significant anti-RBC antibody, donor blood is restricted to RBC units negative for the corresponding antigen; further testing for compatibility is done by combining recipient plasma, donor RBCs, and antihuman globulin. In recipients without clinically significant anti-RBC antibodies, an immediate spin cross-match, which omits the antiglobulin phase, confirms ABO compatibility.

Emergency transfusion is done when not enough time (generally < 60 min) is available for thorough compatibility testing because the patient is in hemorrhagic shock. When time permits (about 10 min is needed), ABO/Rh type-specific blood may be given. In more urgent circumstances, type O RBCs are transfused if the ABO type is uncertain, and Rh-negative blood is given to females of child-bearing age if the Rh type is uncertain; otherwise, either Rh-negative or Rh-positive O blood can be used.

“Type and screen” may be requested in circumstances not likely to require transfusion, as in elective surgery. The patient’s blood is typed for ABO/Rh antigens and screened for antibodies. If antibodies are absent and the patient needs blood, ABO/Rh type specific or compatible RBCs may be released without the antiglobulin phase of the cross-match. If an unexpected antibody is present, full testing is required.

ABO and Rh 0 typing

ABO typing of donor and recipient blood is done to prevent transfusion of incompatible RBCs (see Figure: Compatible RBC types.). As a rule, blood for transfusion should be of the same ABO type as that of the recipient. In urgent situations or when the correct ABO type is in doubt or unknown, type O Rh-negative packed RBCs (not whole blood—see Acute Hemolytic Transfusion Reaction), which contains neither A nor B antigens, may be used for patients of any ABO type.

Compatible RBC types.

Rh typing determines whether the Rh factor Rh0(D) is present on (Rh-positive) or absent from (Rh-negative) the RBCs. Rh-negative patients should always receive Rh-negative blood except in life-threatening emergencies when Rh-negative blood is unavailable. Rh-positive patients may receive Rh-positive or Rh-negative blood. Occasionally, RBCs from some Rh-positive people react weakly on standard Rh typing (weak D, or Du, positive), but these people are still considered Rh-positive.

Antibody screening

Antibody screening for unexpected anti-RBC antibodies is routinely done on blood from prospective recipients and prenatally on maternal specimens. Unexpected anti-RBC antibodies are specific for RBC blood group antigens other than A and B [eg, Rh0(D), Kell (K), Duffy (Fy)]. Early detection is important because such antibodies can cause serious hemolytic transfusion reactions or hemolytic disease of the newborn, and they may greatly complicate compatibility testing and delay procurement of compatible blood.

Indirect antiglobulin testing (the indirect Coombs test) is used to screen for unexpected anti-RBC antibodies. This test may be positive in the presence of an unexpected blood group antibody or when free (non-RBC–attached) antibody is present in autoimmune hemolytic anemias. Reagent RBCs are mixed with the patient’s plasma or serum, incubated, washed, tested with antihuman globulin, and observed for agglutination. Once an antibody is detected, its specificity is determined. Knowing the specificity of the antibody is helpful for assessing its clinical significance, selecting compatible blood, and managing hemolytic disease of the newborn.

Direct antiglobulin testing (the direct Coombs test) detects antibodies that have coated the patient’s RBCs in vivo. It is used when immune-mediated hemolysis is suspected. Patients’ RBCs are directly tested with antihuman globulin and observed for agglutination. A positive result, if correlated with clinical findings and laboratory indicators of hemolysis, suggests autoimmune hemolytic anemia, drug-induced hemolysis, a transfusion reaction, or hemolytic disease of the newborn.

Antibody titration is done when a clinically significant, unexpected anti-RBC antibody is identified in the plasma of a pregnant woman or in a patient with cold agglutinin disease. The maternal antibody titer correlates fairly well with the severity of hemolytic disease in the incompatible fetus and is often used to guide treatment in hemolytic disease of the newborn along with ultrasonography and amniotic fluid study.

Infectious disease testing

Donated blood products are tested for the presence of a number of infectious agents.

Infectious Disease Transmission Testing

Infectious Agent

Type of Testing

Chagas disease

Antibody testing

Hepatitis B core

Antibody testing

Hepatitis B surface

Antigen testing

Hepatitis B virus

Nucleic acid testing*

Hepatitis C virus

Nucleic acid testing and antibody testing


Nucleic acid testing

HIV-1 and HIV-2

Antibody testing

Human T-cell lymphotropic viruses 1 and 2

Antibody testing

Treponema pallidum (syphilis)

Antigen testing

West Nile virus

Nucleic acid testing

Zika virus

Nucleic acid testing

*Nucleic acid testing is useful in the seronegative window period when asymptomatic donors with acute hepatitis B have not yet developed HBsAg or anti-HBc.

If antibody test is positive, infection is confirmed by Western blot or recombinant immunoblotting assay.

Test is available with FDA investigational new drug (IND) status in areas where there is a high risk of infection.

Anti-HBc = antibody to hepatitis B core; HBsAg = hepatitis B surface antigen.

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