hematology and oncology
Complications of Transfusion
Infectious complications
Bacterial contamination of packed RBCs occurs rarely, possibly due to inadequate aseptic technique during collection or to transient asymptomatic donor bacteremia. Refrigeration of RBCs usually limits bacterial growth except for cryophilic organisms such asYersinia, which may produce dangerous levels of endotoxin. All RBC units are inspected before dispensing for bacterial growth, which is indicated by a color change. Because platelet concentrates are stored at room temperature, they have greater potential for bacterial growth and endotoxin production if contaminated. To minimize growth, storage is limited to 5 days. The risk of bacterial contamination of platelets is 1:2500. Therefore, platelets are routinely tested for bacteria. Rarely, Syphilis is transmitted in fresh blood or platelets. Storing blood for Causes of Hepatitis may occur after transfusion of any blood product. The risk has been reduced by viral inactivation through heat treatment of serum Human Immunodeficiency Virus (HIV) Infection in the US is almost entirely HIV-1, although HIV-2 is also of concern. Testing for antibodies to both strains is required. Nucleic acid testing for HIV-1 antigen and HIV-1 p24 antigen testing are also required. Additionally, blood donors are asked about behaviors that may put them at high risk of HIV infection. HIV-0 has not been identified among blood donors. The estimated risk of HIV transmission due to transfusion is 1:1,500,000 to 2,000,000. Cytomegalovirus (CMV) Infection (CMV) can be transmitted by WBCs in transfused blood. It is not transmitted through fresh frozen plasma. Because CMV does not cause disease in immunocompetent recipients, routine antibody testing of donor blood is not required. However, CMV may cause serious or fatal disease in immunocompromised patients, who should receive blood products that are CMV-negative by antibody testing or blood depleted of WBCs by filtration. Human T-cell lymphotropic virus 1 (HTLV-1), which can cause adult T-cell lymphoma/leukemia and HTLV-1–associated myelopathy/tropical spastic paraparesis, causes posttransfusion seroconversion in some recipients. All donor blood is tested for HTLV-1 and HTLV-2 antibodies. The estimated risk of false-negative results on testing of donor blood is 1:641,000. Creutzfeldt-Jakob disease has never been reported to be transmitted by transfusion, but current practice precludes donation from a person who has received human-derived growth hormone or a dura mater transplant or who has a family member with Creutzfeldt-Jakob disease. Variant CJD (vCJD) (vCJD, or mad cow disease) has not been transmitted by blood transfusion. However, donors who have spent significant time in the United Kingdom and some other parts of Europe may be permanently deferred from donation (see table Malaria is transmitted easily through infected RBCs. Many donors are unaware that they have malaria, which may be latent and transmissible for 10 to 15 years. Storage does not render blood safe. Prospective donors must be asked about malaria or whether they have been in a region where it is prevalent. Donors who have had a diagnosis of malaria or who are immigrants, refugees, or citizens from countries in which malaria is considered endemic are deferred for 3 years; travelers to endemic countries are deferred for 1 year. Babesiosis , Zika Virus (ZV) Infections has been reported to be transmitted via blood products in Brazil. Therefore, the FDA has mandated testing for Zika virus in the US and its territories. In lieu of Zika testing, pathogen reduction technologies approved for platelets and plasma could also be used; however, their use is currently very limited, and this technology is still unavailable for red cells. 