Dictionary

This Dictionary of Transfusion and Transplantation Medicine Terminology provides definitions and/or explanatory text for the most common used terms on this website.

British (Oxford Dictionary) recommended spelling has been used. An additional list of alternative spellings is also available.

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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A
Acquired Immune Deficiency Syndrome	(AIDS) The final and most serious stage of infection with the Human Immunodeficiency Virus (HIV), in which the signs and symptoms of severe immune deficiency have developed.
Acute Normovolaemic Haemodilution	(ANH) A method of reducing blood loss during surgery involving the immediate pre-operative collection of whole blood from the patient with the simultaneous infusion of crystalloid or colloid to maintain normovolaemia. The blood is re-infused when required, normally during surgery.
Acute Transfusion Reaction	(ATR) A reaction occurring anytime up to 24hrs following a transfusion of blood or components (2) A SHOT incident category and defined as: Fever and other symptoms/signs of haemolysis within 24 hours of transfusion. Confirmed by a fall in haemoglobin, rise in LDH, positive DAT and positive cross match.
Additive solution	Solution designed to maintain viability of cellular components during storage. Commonly used in UK is saline, adenine glucose mannitol (SAGM).
Adult Therapeutic Dose	(ATD) Refers to the amount usually transfused to an adult in a single dose. Usually used in reference to platelet transfusions.
AIDS	See Acquired Immune Deficiency Syndrome.
Aliquots	A division of a larger portion into smaller parts; used in transfusion to split standard packs of red cells, platelets and FFP into smaller paediatric packs.
Allogeneic blood products	Blood and blood components collected from an individual and intended for transfusion to another individual, for use in medical devices or as starting material or raw material for manufacturing into medicinal products.
Allogeneic donation	Blood donated by another person.
Anaemia	A pathological decrease in red cells in the blood. The ability to carry oxygen is reduced. Anaemia is noted by the haemoglobin content of the red cells and by red cell size.
Anaphylactic reaction	Definition used by SHOT: Hypotension with one or more of: rash, dyspnoea, stridor, wheezing, angioedema, pruritus, urticaria, during or within 24 hrs of transfusion.
ANH	See Acute Normovolaemic Haemodilution.
Antibody	Protein, secreted by specialised blood cells, which will either neutralise antigens or activate other systems which will cause the destruction of the cell on which the antigen is carried.
Anticoagulant	A substance that prevents or delays blood clotting(coagulation).
Anti-D immunoglobulin	Human IgG preparation containing a high level of antibody to the Rh D antigen.
Antigen	Any substance, organism or foreign material recognised by the body as being non-self, which will provoke the production of specific antibodies.
Apheresis	A process in which whole blood is collected from a donor and separated into components. Some of these are retained and the remainder returned to the donor.
Apheresis (single donor) plasma	See Plasma, apheresis.
Apheresis (single donor) platelet concentrate	See Platelets, apheresis.
APTT	Activated partial thromboplastin time.
Artificial colloid solutions	See Colloid solutions (artificial colloids).
ATD	See Adult Therapeutic Dose.
ATR	See Acute Transfusion Reaction.
Autologous Blood Transfusion	Transfusion to an individual of blood collected from him or her self Includes: - pre-deposit autologous donation (PAD) - acute normovolaemic haemodilution (ANH) - salvage from operation site (intra-operative) (ICS) - salvage from operation site (post-operative) (PCS).
B
BBT	"Better Blood Transfusion - Appropriate use of Blood" Programmes promoted by the UK Departments of Health for the conservation and improved management of blood. The programmes are outlined in the respective National Health Service Circulars (copies are available in BBT Toolkit section).
BBTS	British Blood Transfusion Society A professional and scientific society that promotes knowledge and advanced understanding of all aspects of transfusion medicine. For more information go to www.bbts.org.uk.
BCSH	British Committee for Standards in Haematology A committee within the British Society of Haematology publishing national guidelines in the field of Blood Transfusion and Haematology.
Bio Products Laboratory	(BPL) An operating division of NHS Blood and Transplant. (www.bpl.co.uk).
Blood	Whole human blood collected from a donor and processed either for transfusion or for further manufacturing.
Blood component	A therapeutic constituent of human blood (red cells, white cells, platelets, plasma, cryoprecipitate).
Blood component release	A process which enables a blood component to be released from a quarantine status by the use of systems and procedures to ensure that the finished product meets its release specification.
Blood establishment	Organisation responsible for any aspect of the collection and testing of human blood or blood components, whatever their intended purpose, and their processing, storage, and distribution when intended for transfusion. The four UK Blood Services / Blood Transfusion Services (National Blood Service, Northern Ireland Blood Transfusion Service, Scottish National Blood Transfusion Service and the Welsh Blood Service) are blood establishments. Excludes hospital blood banks. (EU Directive 2002/98/EC definition.).
Blood product	Any therapeutic product derived from human whole blood or plasma donations.
Blood Safety and Quality Regulations 2005	UK law implementing the EU Directives - 2002/98/EC and2004/33/EC (Statutory Instrument 2005/50 and subsequent amendments). The regulations set standards for quality and safety for the collection, testing, processing, storage and distribution of human blood and blood components. The regulations apply to "blood establishments" (the UK Blood Services) and Hospital Blood Banks.
Bovine Spongiform Encephalopathy	(BSE) A neurological disease of cattle which is generally thought to have caused the incidence of vCJD in humans.
BPL	See Bio Products Laboratory.
BSE	See Bovine Spongiform Encephalopathy.
BSMS	Blood Stocks Management Scheme Initially a partnership venture between the National Blood Service and hospitals to promote better practice in blood stocks management. The scheme now has participants from the other UK countries. (www.bloodstocks.co.uk).
BSQR	See Blood Safety and Quality Regulations 2005.
Buffy Coat	The granulocyte and platelet layer that forms between red cells and plasma when a pack of whole blood is centrifuged under suitable conditions.
C
CABG	Coronary artery bypass grafting.
Centrifuge	A device for separating components in a liquid by spinning the mixture at high speeds. Centrifugal force causes the heavier substances to move further away from the center of gravity, leaving the lighter substances more central. Blood is centrifuged to separate its components.
Citrate	A compound of citric acid that is used as an anticoagulant.
CJD	See Creutzfeldt-Jakob Disease.
CMV	See Cytomegalovirus.
CNST	Clinical Negligence Scheme for Trusts A scheme which encourages thorough risk management in Trusts by assessment and reward.
Colloid solutions (artificial colloids)	Gelatines, dextrans, hydroxyethyl starch.
Coombs" test	See Direct antiglobulin test.
CPA	Clinical Pathology Accreditation An accreditation scheme for pathology laboratories and blood banks.
CPD	Continued Professional Development.
CPDA	Citrate, Phosphate dextrose adenine: an anticoagulant/nutrient used for the storage of donated blood.
Creutzfeldt-Jakob Disease	(CJD) A fatal neurological disease which affects the brains of the elderly.
Cryoprecipitate	Precipitate produced after freezing and thawing fresh frozen plasma to precipitate high molecular weight proteins including factor VIII and fibrinogen.
Cryoprecipitate-depleted plasma,	See Plasma, cryoprecipitate-depleted.
Cryopreservation	Prolongation of the storage life of blood components by freezing.
Cryosupernatant plasma	Plasma from which the cryoprecipitate has been removed.
Crystalloid solution	Saline, Ringer's lactate etc.
Cytomegalovirus	(CMV) A type of herpes virus which is transmissible via transfusion and can cause infection in immunosuppressed patients.
D
DAGT	See Direct antiglobulin test.
Deferral	Suspension of the eligibility of an individual to donate blood or blood components. Such suspension being either permanent or temporary.
Delayed Transfusion Reaction	(DTR) A delayed reaction occurring as little as 24hours or as long as 21 days following transfusion of blood or components. Nearly always due to secondary immune response. (2) SHOT definition: Fever and other symptoms/signs of haemolysis more than 24 hours after transfusion. Confirmed by fall in Hb, rise in bilirubin, positive DAT and positive cross match not detectable pre-transfusion. Simple serological reactions (development of antibody without pos DAT or evidence of haemolysis)are excluded.
Dextran	A colloid solution.
DH / DOH	Department of Health (www.dh.gov.uk).
DIC	Disseminated intravascular coagulation.
Direct antiglobulin test	(DAGT) (Coombs'test) Sensitive method to detect red cell bound antibody.
DTR	See Delayed Transfusion Reaction.
E
EBMP	Emergency Blood Management Plan Emergency Planning: Development of an integrated plan for the management of blood shortages. A plan outlined by the Department of Health to manage potential shortages of blood www.dh.gov.uk.
Emerging infectious disease	A newly recognised, clinically distinct infectious disease, or a known disease whose reported incidence within the past two decades is increasing in a given place or among a specific population (Health Protection Agency definition).
EPO	Abbreviation for recombinant human erythropoietin.
Epoetin	Approved name for recombinant human erythropoietin.
Erythropoietin	A hormone produced by the kidney that stimulates red cell production by bone marrow.
EUB	Effective Use of Blood group (Scotland).
F
Facilities	Hospitals, clinics, manufacturers, and biomedical research institutions to which blood or blood components may be delivered (Commission Directives on haemovigilance/traceability).
Factor VIII	A clotting factor which stabilises blood clots.
FFP	See Fresh Frozen Plasma.
Fresh Frozen Plasma	(FFP) Plasma that is frozen within a specific time period after collection and stored in the frozen state until thawed for transfusion or used for fractionation.
G
GMP	Good Manufacturing Practice Guidelines designed to ensure that products are safe to use. The UK Blood Services must conform to GMP when producing products and components.
Graft versus Host Disease	(GvHD) A serious condition in which allogeneic lymphocytes attack the tissues of the individual to whom they have been transplanted or transfused.
Granulocytes, apheresis	a concentrated suspension of granulocytes obtained by apheresis.
GvHD	See Graft versus Host Disease.
H
Haematinics	Substances, such as iron and folic acid, which are necessary for haemoglobin and red cell production.
Haematocrit	A measure of the number of red cells found in the blood, stated as a percentage of the total blood volume. The normal range is between43 and 49% in men, and between 37% and 43% in women.
Haematoma	A swelling or mass of blood (usually clotted) confined to an organ, tissue or space and caused by a break in a blood vessel.
Haemoglobin	A complex protein-iron compound in the blood that carries oxygen to the cells from the lungs and carbon dioxide away from the cells to the lungs. Each red blood cell contains 200 to 300 molecules of haemoglobin. Each molecule of haemoglobin contains several molecules of haem, each of which can carry one molecule of oxygen. The normal concentration is between 12.5 and 16 g/dl.
Haemolysis	The breakdown of red blood cells and the release of haemoglobin. It occurs normally at the end of the life span of a red cell. However, it may occur under many other circumstances, as when fighting off disease or as a side effect of haemodialysis or artificial heart aids, as pacemakers. Adding excessive liquid to the blood by vein can also cause haemolysis.
Haemolytic Disease of the Newborn	(HDN) A condition in which foetal red cells are destroyed by maternal antibody, usually anti D.
Haemolytic reaction, acute intravascular	The situation in which antibodies in the recipient's blood destroy transfused red cells within the blood vessels. This causes a multitude of problems, including renal failure and major clotting defects, and may be fatal.
Haemostasis	The stopping of bleeding by mechanic or chemical means or by the complex clotting process of the body.
Haemostatic agents	Materials or drugs used to assist the control of bleeding.
Haemovigilance	a set of organised surveillance procedures relating to serious adverse or unexpected events or reactions in donors or recipients, and the epidemiological follow-up of donors.
HAS	Human Albumin Solution A pharmaceutically produced blood component available in different strengths and volumes.
HAV	Hepatitis A virus.
HbsAg	Hepatitis B surface antigen The presence or absence of this surface antigen is used to determine whether blood is infected with Hepatitis B virus.
HBV	See Hepatitis B virus.
HC / HSC	Health Circular / Health Service Circular.
HCV	See Hepatitis C virus.
HDN	See Haemolytic Disease of the Newborn.
Heparin	A naturally occurring substance that acts in the body to prevent clotting in the veins. It is produced in the connective tissue surrounding capillaries, particularly in the lungs and liver.
Hepatitis B virus	(HBV) The pathogen causing Hepatitis B also called serum hepatitis. A form of hepatitis having rapid onset of sudden symptoms and signs. The virus can be carried in blood products or by the use of non sterile needles and instruments. The infection may be severe and result in prolonged illness, destruction of liver cells, cirrhosis and can be fatal.
Hepatitis C virus	(HBC) The pathogen causing Hepatitis C. Transmitted through direct body fluid contact such as blood transfusion or shared use of needles by intravenous drug users. The disease progresses to chronic hepatitis in up to 50% of the patients acutely infected. Diagnosis is made through identification of antibodies.
Hetastarch	A substance to increase the volume of blood plasma, given to help treat shock and leucopheresis.
HGV-C or GBV-C	Hepatitis G virus; a recently described virus of uncertain significance.
HIV	See Acquired Immune Deficiency Syndrome.
HLA	Human Leucocyte Antigen.
Homologous	From the same species. Used to describe blood from another human, rather than one's own blood (autologous).
Hospital blood bank	Any unit within a hospital which stores and distributes, and may perform compatibility tests on, blood and blood components exclusively for use within hospital facilities, including hospital based transfusion activities.
HPA	Human Platelet Antigen.
HPC	Health Professions Council.
HTC	Hospital Transfusion Committee.
HTLV I	Human T-cell leukaemia virus type I.
HTR	Haemolytic Transfusion Reaction A SHOT incident category.
HTT	Hospital Transfusion Team.
Human parvovirus B19	A non-enveloped virus transmissible by blood products and potentially pathogenic in some groups of patients.
I
IBCT	Incorrect Blood Component Transfused A SHOT incident category.
IBGRL	International Blood Group Reference Laboratory.
IBMS	Institute of Biomedical Science.
ICP	Integrated Care Pathway.
ICS	See Autologous Blood Transfusion.
Immune globulin	Also called gamma globulin. Passive immunizing agents obtained from pooled human plasma.
Irradiation / Irradiated Blood components	Cellular blood component treated with 25 gray (Gy) gamma irradiation to inactivate lymphocytes that could cause graft-versus-host disease in a recipient.
ISBT	International Society for Blood Transfusion.
J
JPAC	The Joint United Kingdom Blood Transfusion Services /National Institute for Biological Standards and Control Professional Advisory Committee (www.transfusionguidelines.org.uk).
K
Kleihauer test	A method for counting of foetal cells in maternal blood.
L
LD	See Leucodepleted.
Leucodepleted	(LD) Blood component from which white cells have been removed by filtration or another method.
Leukocytes	White blood cells. The blood cells involved in fighting infection, producing antibodies and rejecting foreign cells.
M
Massive transfusion	Variously defined as the replacement of one blood volume within 24 hours, or of 50% blood volume loss within three hours, or a rate of loss of 150 ml per minute in adults. In children it is usually defined as the loss of one blood volume within 24 hours, or 50% blood volume within three hours, or a rate of loss of 2−3 ml/kg per minute.
Medicines and Healthcare products Regulatory Agency	(MHRA) UK body responsible for the licensing of pharmaceuticals and blood service activities.
MHRA	See Medicines and Healthcare products Regulatory Agency.
MSBOS (SBOS)	Maximum Surgical Blood Order Schedule (Surgical Blood Order Schedule) Schedule of the normal quantities of blood ordered by type of surgical procedure, set at hospital level.
MSBTO	The Advisory Committee on Microbiological Safety of Blood, Tissues and Organs of the Department of Health (www.advisorybodies.doh.gov.uk/acmsbtt).
N
NAIT	Neonatal alloimmune thrombocytopenia.
NANB hepatitis	Non A non B hepatitis: former operational term for the most common class of post-transfusion hepatitis. Now known to be largely due to hepatitis C virus, and >80% eliminated by HCV screening of donations.
National Blood Service	(NBS) An operating division of NHS Blood and Transplant. A Blood Establishment operational in England and North Wales.(www.blood.co.uk).
NBS	See National Blood Service.
NBTC (NTC)	National Blood Transfusion Committee.
NEQAS	National External Quality Assessment Service.
NHS Blood and Transplant	(NHSBT) A Special Health Authority within the NHS responsible for managing the: National Blood Service (NBS) UK Transplant (UKT) Bio Products Laboratory (BPL) (www.nhsbt.nhs.uk).
NHSBT	See NHS Blood and Transplant.
NHSLA	NHS Litigation Authority.
NIBSC	National Institute for Biological Standards and Control.
NIBTS	See Northern Ireland Blood Transfusion Service.
NICE	National Institute for Health and Clinical Excellence (www.nice.org.uk).
Normal microbiological markers	In the UK, blood is normally screened for HIV 1 & 2(the human immunodeficiency or AIDS virus), hepatitis B and C and syphilis.
Northern Ireland Blood Transfusion Service	(NIBTS) A Blood Establishment operational in Northern Ireland. (www.nibts.org).
NPSA	National Patient Safety Agency.
O
Optimal additive solution	A fluid added to a red cell concentrate after the plasma has been removed. This fluid contains both nutrients for the red cells and substances to control the acidity of the blood. Most commonly used solution in the UK is SAGM.
P
Packed Red Cells	A synonym used to describe red cells.
PAD	See Autologous Blood Transfusion.
Pathogen reduction	Additional manufacturing step in making blood products, validated to remove or substantially reduce infectivity for infectious agents. Some viruses may not be reliably inactivated by current methods.
PCS	See Autologous Blood Transfusion.
Perfusionist	A person who, under the supervision of a physician, operates a heart-lung machine used for cardiopulmonary bypass during surgery.
PHLS	Public Health Laboratory Service Responsible for monitoring public health and infectious diseases.
Plasma	The liquid portion of the blood in which the cells are suspended. Plasma may be separated from the cellular portion of a whole blood collection for therapeutic use as fresh frozen plasma or further processed to cryoprecipitate and cryoprecipitate-depleted plasma for transfusion. It maybe used for the manufacture of medicinal products derived from human blood and human plasma, or used in the preparation of pooled platelets, or pooled leucocyte-depleted platelets. It may also be used for resuspension of red cell preparations for exchange transfusion or perinatal transfusion.
Plasma derivative	Licensed pharmaceutical product containing partially purified human plasma protein for therapeutic use. Prepared from pooled human plasma under pharmaceutical manufacturing conditions e.g. coagulation factors, immunoglobulins, albumin.
Plasma fractions	Partially or highly purified human plasma proteins prepared from pooled human plasma under pharmaceutical manufacturing conditions (GMP) and generally licensed by MHRA e.g. coagulation factors, immunoglobulins, albumin.
Plasma, apheresis	Plasma prepared by apheresis of the donor.
Plasma, cryoprecipitate-depleted	Plasma component prepared from a unit of plasma, fresh-frozen. It comprises the residual portion after the cryoprecipitate has been removed.
Plasma, fresh frozen	The supernatant plasma separated from a whole blood donation or plasma collected by apheresis, frozen and stored.
Platelet	Thrombocyte, the smallest of the cells in the blood. Platelets are disk-shaped and have no haemoglobin. They are needed for blood clotting. They have a useful shelf-life of up to 5 days.
Platelets, apheresis	Platelets prepared by apheresis of the donor.
Platelets, apheresis, leucocyte-depleted	A concentrated suspension of blood platelets, obtained by apheresis, from which leucocytes are removed.
Platelets, recovered, pooled	A concentrated suspension of blood platelets, obtained by processing of whole blood units and pooling the platelets from the units during or after separation.
Platelets, recovered, pooled, leucocyte-depleted	A concentrated suspension of blood platelets, obtained by the processing of whole blood units and pooling the platelets from the units during or after separation, and from which leucocytes are removed.
Post Transfusion Purpura	(PTP) Immunological mediated thrombocytopenia following transfusion (2) A SHOT incident category and defined as: Thrombocytopenia within 12 days after transfusion of red cells, associated with presence in patient of antibodies directed against the HPA systems.
PTH	Post-transfusion hepatitis.
PTP	See Post Transfusion Purpura.
Q
R
RAADP	See Routine Antenatal Anti D Prophylaxis.
RAFT	Regulatory Authority for Fertility and Tissue.
RBRP	Right Blood to Right Patient A SHOT incident category.
RCN	Royal College of Nursing.
Recovered ("random donor")	Platelets prepared from individual donations of whole blood platelet concentrate.
Recovered plasma	Plasma prepared from individual donations of whole blood.
Red Book	In service terminology for the publication "Guidelines for the Blood Transfusion Services in the United Kingdom".
Red cells	In the context of transfusion medicine, the term is used for any red cell component from a single whole blood donation, with a large proportion of the plasma from the donation removed.
Red cells in additive solution	The red cells from a single whole blood donation, with a large proportion of the plasma from the donation removed. A nutrient or preservative solution is added.
Red cells, apheresis	The red cells from an apheresis red cell donation.
Red cells, buffy coat removed	The red cells from a single whole blood donation, with a large proportion of the plasma from the donation removed. The buffy coat, containing a large proportion of the platelets and leucocytes in the donated unit, is removed.
Red cells, buffy coat removed, in additive solution	The red cells from a single whole blood donation, with a large proportion of the plasma from the donation removed. The buffy coat, containing a large proportion of the platelets and leucocytes in the donated unit, is removed. A nutrient or preservative solution is added.
Red cells, leucocyte-depleted	The red cells from a single whole blood donation, with a large proportion of the plasma from the donation removed, and from which leucocytes are removed.
Red cells, leucocyte-depleted, in additive solution	The red cells from a single whole blood donation, with a large proportion of the plasma from the donation removed, and from which leucocytes are removed. A nutrient or preservative solution is added.
Reporting establishment	The blood establishment, the hospital blood bank or facilities where the transfusion takes place that reports serious adverse reactions and/or serious adverse events to the competent authority(Commission Directives on haemovigilance/traceability).
Rh D	The Rh D red cell antigen.
Routine Antenatal Anti D Prophylaxis	(RAADP) A programme established to reduce the incidence of HDN.
RTC	Regional Transfusion Committee.
S
SABRE	Serious Adverse Blood Reactions and Events.
SACBC	Standing Advisory Committee for Blood Components A sub-committee of JPAC.
SACCSD	Standing Advisory Committee on Care and Selection of Donors A sub-committee of JPAC.
SACCTM	Standing Advisory Committee on Clinical Transfusion Medicine A sub-committee of JPAC.
SACIH	Standing Advisory Committee on Immunohaematology A sub-committee of JPAC.
SACIT	Standing Advisory Committee on Information Technology A sub-committee of JPAC.
SACSC	Standing Advisory Committee on Stem Cells A sub-committee of JPAC.
SACT	Standing Advisory Committee on Tissues A sub-committee of JPAC.
SACTTI	Standing Advisory Committee on Transfusion Transmitted Infection A sub-committee of JPAC.
SAGM	See Additive solution.
Saline	Sodium chloride intravenous infusion 0.9%.
SBOS	See MSBOS (SBOS).
Scottish National Blood Transfusion Service	(SNBTS) A Blood Establishment operational in Scotland.(www.snbts.org.uk).
SEAC	Spongiform Encephalopathy Advisory Committee A non-NBS committee of experts that advises the UK government on issues relating to vCJD and BSE.
Serious Adverse Blood Reactions and Events	A reporting system for reporting serious adverse reactions and events to MHRA and SHOT (Blood Safety and Quality Regulations 2005).
Serious adverse event	Any untoward occurrence associated with the collection, testing, processing, storage and distribution, of blood or blood components that might lead to death or life-threatening, disabling or incapacitating conditions for patients or which results in, or prolongs, hospitalization or morbidity.
Serious adverse reaction	An unintended response in a donor or in a patient associated with the collection or transfusion of blood or blood components that is fatal, life-threatening, disabling, or which results in or prolongs hospitalization or morbidity.
Serious Hazards of Transfusion	(SHOT) UK reporting system for adverse transfusion events and "near misses".
Severe allergic reaction	Definition used by SHOT: A severe allergic reaction with immediate risk to life occurring during or within 24 hours of transfusion, characterised by bronchospasm causing hypoxia, or angioedema causing respiratory distress.
SHOT	See Serious Hazards of Transfusion.
Site	Any premises at which a blood establishment carries out any of the activities listed in regulation 3(2), but shall not include any premises not owned or managed by the blood establishment at which blood is collected, or any mobile blood collection unit.
SNBTS	See Scottish National Blood Transfusion Service.
Specialist Practitioner of Transfusion	(SPOT) A nurse, Biomedical Scientist, medical professional or equivalent with specialist knowledge of Blood Transfusion.
SPOT	(1) A forum that promotes knowledge and advanced understanding of transfusion medicine for transfusion practitioners, working in partnership with other professional bodies (www.bloodspot.org) (2)See Specialist Practitioner of Transfusion.
T
TA-GvHD	See Graft versus Host Disease.
Thrombocytopenia	An abnormally low platelet count which may indicate a bleeding risk.
Tissue establishment	A tissue bank or a unit of a hospital or another body where activities of processing, preservation, storage or distribution of human tissues and cells are undertaken. It may also be responsible for procurement or testing of tissues and cells (Directive 2004/23/EC).
TPH	Transplacental haemorrhage.
Traceability	The ability to trace each individual unit of blood or blood component derived thereof from the donor to its final destination, whether this is a recipient, a manufacturer of medicinal products or disposal, and vice versa (Commission Directives on haemovigilance/traceability).
TRALI	See Transfusion Related Acute Lung Injury.
Transfusion associated graft versus host disease	(TA-GvHD) See Graft versus Host Disease. (2) A SHOT incident category.
Transfusion Related Acute Lung Injury	(TRALI) Acute lung injury following within hours of a transfusion (2) A SHOT incident category and defined as: Acute dyspnoea with hypoxia and bilateral pulmonary infiltrates during or within 6 hrs of transfusion, not due to circulatory overload or other likely cause.
Transfusion Transmissible Infection	(TTI) A SHOT incident category and a report would be classified as such if, following investigation: - The recipient had evidence of infection post-transfusion, and there was no evidence of infection prior to transfusion and no evidence of an alternative source of infection And, either - At least one component received by the infected recipient was donated by a donor who had evidence of the same transmissible infection, or - At least one component received by the infected recipient was shown to contain the agent of infection.
Transfusion trigger	An agreed haematocrit or haemoglobin concentration, below which a patient should receive a blood transfusion.
TSE	Transmissible spongiform encephalopathy.
TTI	See Transfusion Transmissible Infection.
TTP	Thrombotic Thrombocytopenic Purpura.
U
UK Transplant	(UKT) An operating division of NHS Blood and Transplant(www.uktransplant.org.uk).
UKBTS	See United Kingdom Blood Transfusion Services.
UKBTS Web Site	UK Blood Transfusion & Tissue Transplantation website. The site is managed by JPAC and aims to provide guidelines, information and best clinical practice relevant to Blood Transfusion and Tissue Transplantation in the UK. (www.transfusionguidelines.org.uk).
UKT	See UK Transplant.
United Kingdom Blood Transfusion Services	(UKBTS) National Blood Service (NBS),Northern Ireland Blood Transfusion Service (NIBTS) Scottish National Blood Transfusion Service(SNBTS) Welsh Blood Service (WBS).
V
Validation	The establishment of documented and objective evidence that the particular requirements for a specific intended use can be consistently fulfilled.
variant Creutzfeldt-Jakob Disease	(vCJD) Fatal human disease thought to be caused by the same agent as Bovine Spongiform Encephalopathy.
vCJD	See variant Creutzfeldt-Jakob Disease.
Viral inactivation	See Pathogen reduction.
Vitamin B12	A red, crystal-like substance that can be dissolved in water, important as a vitamin. It is used in processing protein, fats, and carbohydrates, normal blood making, and nerve function. The first substance with cobalt found to be vital to life, cyanocobalamin cannot be made in a laboratory but can be taken from cultures of Streptomyces griseus. Rich dietary sources are liver, kidney, meats, fish, and dairy products. A lack is most often caused by the lack of a substance made in the small intestine(intrinsic factor). Intrinsic factor is needed for the taking up of cyanocobalamin from the digestive tract. A lack of cyanocobalamin results in pernicious anaemia and brain damage.
W
Washed	A process of removing plasma or storage medium from cellular products by centrifugation, decanting of the supernatant liquid from the cells and addition of an isotonic suspension fluid, which in turn is generally removed and replaced following further centrifugation of the suspension. The centrifugation, decanting, replacing process may be repeated several times.
WBS	See Welsh Blood Service.
Welsh Blood Service	(WBS) A Blood Establishment operational in (South) Wales.(www.welsh-blood.org.uk).
Whole Blood	Blood collected from a donor before separation into red cells, platelets, and plasma. Whole blood is now very rarely transfused\|.
X
Y
Z