Administration \200 Intensive regimen with severe myelosuppression. \200 Discuss risk o f infertility and consider sperm storage or egg-harvesting. \200 Consider IV hydration fo r patients with bulk disease. \200 Allopurinol 300mg od PO (100mg if creatinine clearance <20mL/ min) for fi rst 4 weeks. Antiemetic therapy for highly emetogenic regimens. \200 Commence H2 antagonist or PPI. \200 Oral systemic Pneumocystis jirovecii prophylaxis according to local protocol recommended (generally co-trimoxazole 480mg bd 3d per week) throughout treatment a nd for 8 weeks after completion. Antifungal and antiviral prophylaxis. \200 Consider regular laxatives. \200 In patients with renal impairment, when creatinine clearance <60mL/min administer 80% mustine dose, 85% etoposide dose and 75% bleomycin dose; <30mL/min omit mustine, administer 75% etoposide dose <60mL/min. 744 CHAPTER 15 Protocols and procedures In patients with hepatic dysfunction, if bilirubin 1 \200\2232 \227 ULN reduce doxorubicin , vinblastine, vincristine and etoposide doses to 50%; 2 \200\2234 \227 ULN reduce doses t o 25%; >4 \227 ULN omit doxorubicin, vinblastine, and etoposide. If neutrophils 0.5 \200\2231.0 \227 109/L, administer 65% doses of doxorubicin, mustine, v incristine and etoposide but 100% dose of other drugs; if <0.5 \227 109/L delay doxorubici n, mustine, vincristine and etoposide by 1 week but no delay or dose reduction of other dru gs. If dose reduction or delay is required, administer G-CSF SC on d3 \200\2237 and d17 \200\22321 of each cycle. No dose reductions or delay if platelets >10 \227 109/L; if <10 \227 109/L, transfuse platelets to maintain count >10 \227 109/L. 745 Chapter 16 Hematological investigations Full blood count 746 Blood fi lm 746 Plasma viscosity 746 ESR 747 Haematinic assays 747 Hem oglobin electrophoresis 747 Haptoglobin 748 Schumm \200\231s test 748 Kleihauer test 748 Re ticulocytes 749 Urinary haemosiderin 750 Ham \200\231s test 751 Immunophenotyping 752 Cytog enetics 754 Human leucocyte antigen (HLA) typing 756 746 CHAPTER 16 Hematological investigations Full blood count Rapid analysis by the latest-generation automated blood counters using eit her forward-angle light scatter or impedance analysis provides enumer- ation of leucocytes, erythrocytes, and platelets and quantifi cation of hemoglobin and MCV, plus derived values for haematocrit, MCH, and MCHC, red cell distribution width (a measure of cell size scatte r), mean platelet volume and platelet distribution width, and a 5-parameter diff erential l eucocyte count. The counter also fl ags samples which require direct morphological assessme nt by examination of a blood fi lm. Sample: peripheral blood EDTA; the sample should be ana lyzed in the laboratory within 4h. Blood \201 lm Morphological assessment of red cells, leucocytes, and platelets should be performed by an experienced individual of all samples in which the FBC has revealed any res ult signifi cantly outside the n range, samples in which a fl ag has been indicated by the automated counter and if clinically indicated. A manual diff erential leucocyte count may b e performed and may diff er from that produced by the automated counter most notably in pat ients with hematological disease aff ecting the leucocytes. Sample: peripheral blood EDTA; the sample should be analyzed in the laboratory within 4h. May be made directly from drop o f blood or EDTA sample, air-dried, and fi xed. Plasma viscosity This test is a sensitive but non-specifi c index of plasma protein changes which result from infl ammation or tissue damage. The plasma viscosity is unchanged by hae matocrit variations and delay in analysis up to 24h and is therefore more reliable than the ESR. It is not aff ected by sex but is aff ected by age, exercise, and pregnancy. Sample: peripheral blood EDTA; the sample should be analyzed in the laboratory within 24h. 747 ESR ESR This test is a sensitive but non-specifi c index of plasma protein changes which result from infl ammation or tissue damage. The ESR is aff ected by haematocrit variations, red c ell abnormalities (e.g. poikilocytosis, sickle cells), and delay in analysis and is therefo re less reliable than measure- ment of the plasma viscosity. The ESR is aff ected by age, s ex, menstrual cycle, pregnancy, and drugs (e.g. OCP, steroids). Sample: peripheral blood ED TA; the sample should be analyzed in the laboratory within 4h. Haematinic assays Measurement of the serum B12 and red cell folate are necessary in the inv estigation of macrocytic anemia, and serum ferritin in the investiga- tion of microcytic an emia, in order to assess body stores of the relevant haematinic(s). Serum folate levels are an unreliable measurement of body stores of folate. The serum ferritin may be elevated as an acute phase protein in patients with underlying neoplasia or infl ammatory disease (e.g. rheumatoid arthritis) and may give an erroneously n level in an Fe defi cient patient. Sam ple: clotted blood sample and peripheral blood EDTA. Hemoglobin electrophoresis This test is performed in the diagnosis of abnormal hemoglobin p roduc- tion (haemoglobinopathies or thalassaemia). It is usually performed on cellulose ace tate at alkaline pH (8.9) but may be performed on citrate agar gel at acid pH (6.0) to dete ct certain haemoglobins more clearly. Hemoglobin electrophoresis has been largely replaced by HPLC analysis. Sample: peripheral blood EDTA. 748 CHAPTER 16 Hematological investigations Haptoglobin The serum haptoglobin should be measured in patients with suspected haemolysis (extravascular or intravascular) and is frequently reduced in patients with haemolysis. Low concentrations of haptoglobin may be found in hepatocellular disease. It should generally be accompanied by estimation of the serum methaemalbumin, free plasma hemoglobin, and urina ry haemosiderin. Sample: clotted blood. Schumm \200\231s test This spectrophotometric test for methaemalbumin (which has a distinc- tive absorption band at 558nm) should be measured in patients with suspected intravascular haemolysis and may be abnormal in patients with signifi cant extravascular (generally sple nic) haemolysis. It should generally be accompanied by estimation of the serum haptoglobin level, free plasma hemoglobin, and urinary haemosiderin. Sample: heparinized blood or clott ed blood. Kleihauer test The Kleihauer test which exploits the resistance of fetal red cells to acid elution should be performed on all Rh(D) \210\222ve women who deliver a Rh(D) +ve infant. Fetal cells appear as darkly staining cells against a back- ground of ghosts. An estimate o f the required dose of anti-D can be made from the number of fetal cells in a low power fi eld. Sample: maternal peripheral blood EDTA. 749 RETICULOCYTES Reticulocytes De \201 nition \200 Immature RBCs formed in marrow and found in normal peripheral blood. Represent an intermediate maturation stage in marrow between the nucleated red cell and the mature red cell. No nucleus but retain some nucleic acid. Detection and measurement \200 Demonstrated by staining with supravital dye for the nucle ic acid. \200 Appear on blood fi lm as larger than mature RBCs with fi ne lacy blue staining strands or dots. Some modern automated blood counters using laser technology can measure levels of reticulocytes directly. Usually expressed as a % of total red cells, e.g. 5%, though absolute numbers can be derived from this and total red cell count. Causes of i reticulocyte counts Marrow stimulation due to: \200 Bleeding. \200 Haemolys is. \200 Response to oral Fe therapy. \200 Infection. \200 Infl ammation. \200 Poly cythaemia (any cause). \200 MPDs. \200 Marrow recovery following chemotherapy or radiot herapy. \200 EPO administration. Causes of d reticulocyte counts Marrow in \201 ltration due to: \200 Leukemia. \200 My eloma. \200 Lymphoma. \200 Other malignancy. Marrow underactivity (hypoplasia) due to: \200 Fe, folate, or B12 defi ciency. Note: retu rn of reticulocytes is earliest sign of response to replacement therapy. Immediately post-chemotherapy or radiotherapy. \200 Autoimmune disease especially rheumat oid arthritis. \200 Malnutrition. \200 Uraemia. \200 Drugs. \200 Aplastic anemia (E see p.102). \200 Red cell aplasia (E see p.106). 750 CHAPTER 16 Hematological investigations Urinary haemosiderin Usage The most widely used and reliable test for detection of chronic intravas- cular haemo lysis. Principle Free Hb is released into the plasma during intravascular haemolysis. The hemoglob in binding proteins become saturated resulting in passage of haem-containing compounds into the urinary tract of which haemosid- erin is the most readily detectable. Method \200 A clean catch sample of urine is obtained from the patient. \200 Sample is spun down in a cytocentrifuge to obtain a cytospin preparation of urothelial cells. Staining and rinsing with Perl \200\231s reagent (Prussian blue) is performed on the glass slides. Examine under oil-immersion lens of microscope. \200 Haemosiderin stains as blue dots wit hin urothelial cells. \200 Ignore all excess stain, staining outside cells or in debris a ll of which are common. True +ve is only when clear detection within urothelial squames is seen. Cautions An Fe-staining +ve control sample should be run alongside test case to ensure stai n has worked satisfactorily. Haemosiderinuria may not be detected for up to 72h after the i nitial onset of intravascular haemolysis so the test may miss haemolysis of very recent ons et \200\224repeat test in 3 \200\2237d if \210\222ve. Conversely, haemosiderinuria may per sist for some time after a haemolytic process has stopped. Repeat in 7d should confi rm. Causes See Table 16.1. Table 16.1 Causes of haemosiderinuria Common causes \200 Red cell enzymopathies, e.g. G6PD and PK defi ciency but only during haemolytic episodes Mycoplasma pneumonia with anti-I cold haemagglutinin \200 Sepsis \200 Malaria \200 Co ld haemagglutinin disease TTP/HUS \200 Severe extravascular haemolysis (may cause intravascular haemolysis) PNH \200 Prosthetic heart valves \200 Red cell incompatible transfusion reactions \200 Unstable haemoglobins \200 March haemoglobinuria Rarer causes 751 HAM \200\231S TEST Ham \200\231s test Usage Diagnostic test for paroxysmal nocturnal haemoglobinuria (PNH). Now replaced by immun ophenotyping methods. Principle \200 Abnormal sensitivity of RBCs from patients with PNH to the haemolytic action of complement. Complement is activated by acidifi cation of patient \200\231s serum to pH of 6.2 which induces lysis of PNH red cells but not n controls. Speci \201 city: high \200\224similar reaction is produced only in the rare syndrome HEMPA S (a form of congenital dyserythropoietic anemia type II) which should be easily distinguis hed morphologically. Sensitivity: low \200\224as the reaction is crucially dependent on the concentra- tion of m agnesium in the serum. It appears to be a technically diffi cult test in most laboratories. Patients with only a l ow % of PNH cells may be missed at an early stage of the disease. Markedly abnormal PNH cel ls are usually picked up in 775% of patients. Less abnormal cells are detected in only 725% of patients. Alternative tests \200 Sucrose lysis \200\224an alternative method of complement activati on is by mixing serum with a low ionic strength solution such as sucrose. \200 Sensitivity of this test is high but specifi city is low \200\224i.e. the opposite of Ham \200\231s test. Immunophenotypic detection of the defi ciency of the PIG transmembrane protein anchors in PNH cells is becoming a more widely used alternative cf. P NH section. Monoclonal antibodies to CD59 or CD55 (DAF) are used in fl ow cytometric analys is. Major advantage is that test can be performed on neutrophils and platelets in PB which are more numerous than the PNH red cells. 752 CHAPTER 16 Hematological investigations Immunophenotyping De \201 nition Identifi cation of cell surface proteins by reactivity with monoclonal anti - bodies of known specifi city. Uses \200 Aids diagnosis and classifi cation of hematological malignancy. Assess cellular clonality. Identify prognostic groups. \200 Monitor minimal residual disease (MRD). \200 The adven t of immunophenotyping (or \200\230fl ow \200\231), together with cyto- genetics, has led to new disease classifi cation systems (such as the WHO Classifi cation of Tumors of the Ha ematopoietic and Lym- phoid Tissues), moving away from historical classifi cations solely b ased on morphology. Terminology and methodology Cell surface proteins are denoted according to their cluster di ff eren- tiation (CD) number. These are allocated after international work- shops defi ne i ndividual cell surface proteins by reactivity to monoclonal antibodies. Most cells will exp ress many such proteins and pattern of expression allows cellular characterization. Monoclonal antibodies (MoAbs) MoAbs are derived from single B-lymphocyte cell lines and hav e iden- tical antigen binding domains (idiotypes). It is easy to generate large quantities of MoAbs for diagnostic use. \200 Cell populations from, e.g. PB or BM, or cell suspensio ns are incu- bated with a panel of MoAbs, e.g. anti-CD4, anti-CD34 which are directly or in directly bound to a fl uorescent marker antibody, e.g. FITC (fl uorescein isothiocyanate). The sample is passed through a fl ow-cytometer, a fl uorescence- activated cell sorter (FACS) machine. By assessing forward and side light scatter of the laser, the FACS instruments assign cells to a graphical plot by virtue of cell size and granularity. Allows subpopulations of cells, e.g. mononuclear cells in blood sample to be selected. The reactivity of this cell subpopulation to the MoAb panel can then be determined by fl uorescence for each MoAb. Common diagnostic pro \201 les \200 AML \200 Common ALL CD10 and TdT +ve. \200 T-ALL CD3, CD7, TdT +ve. \200 B-ALL CD10, CD19, surface Ig +ve. \200 CLL CD5, CD19, CD23, we ak surface Ig +ve. CD13+, CD33+, CD 34, CD14 +ve. 753 IMMUNOPHENOTYPING Clonality assessment Particularly useful in determining whether there is a monoclonal B cel l or plasma cell population. \200 2 Monoclonal B cells from, e.g. NHL will have surface e xpression of or light chains but not both. 2 Polyclonal B cells from, e.g. patient with infectious mononucleosis will have both and expression. 754 CHAPTER 16 Hematological investigations Cytogenetics Acquired somatic chromosomal abnormalities are common in haemato- logical mali gnancies. Determination of patterns of cytogenetic abnormali- ties is known as karyotyping. E See Table 16.2 for examples. Uses \200 Aid diagnosis and classifi cation of hematological malignancy. \200 Assess cl onality. \200 Identify prognostic groups. \200 Monitor MRD. \200 Determine engraftmen t and chimerism post-allogeneic transplant. Terminology \200 Normal somatic cell has 46 chromosomes; 22 pairs plus XX or XY. \200 N umbered 1 \200\22322 in decreasing size order. \200 2 arms meet at centromere \200\224sho rt arm denoted p, long arm denoted q. Usually only visible during condensation at metaphase. \200 Stimulants and cell culture u sed \200\224colchicine to arrest cells in metaphase. Stained to identify regions and bands, e.g. p1, q3. Common abnormalities \200 See Table 16.2 \200 Whole chromosome gain, e.g. trisomy 8 (+8 ). \200 Whole chromosome loss, e.g. monosomy 7 ( \210\2227). \200 Partial gain, e.g. 9q + or partial loss, e.g. 5q \210\222. \200 Translocation \200\224material repositioned to another chromosome; usually reciprocal, e.g. t(9;22) \200\224the Philadelphia (Ph) translocation. Inversion \200\224part of chromosome runs in opposite direction, e.g. inv(16) in M4Eo. Many translocations involve point mutations known as oncogenes, e.g. BCR, ras, myc, bcl-2. Molecular cytogenetics \200 Molecular revolution is further refi ning the specifi c abnor malities in the genesis of hematological malignancies. Techniques such as FISH and PCR can detect tiny amounts of abnormal genes. BCR-ABL probes are now used in diagnosis and monitoring of treatment response in CML. IgH and T-cell receptor (TCR) genes are useful in determining clonality of suspected B and T cell tumors respectively. Specifi c probes may be used in diagnosis and monitoring of subtypes of AML, e.g. PML-RARA in AML M3. 755 CYTOGENETICS Table 16.2 Common karyotypic abnormalities CML t(9;22) Ph chromosome translocation creates BCR-ABL. AML t(8;21) t(15;17) inv(16) \210\2225, \210\2227 AML M2, involves AML-ETO genes \200\224has better prognosis. AML M3 involves PML-RARA genes \200\224has better prognosis. AML M4Eo \200\224has better prognosis. Complex abnormalities have poor prognosis. MDS \210\2227, +8, +11 5q \210\222 syndrome Poor prognosis. Associated with refractory anemia and better prognosis. MPD 20q \210\222 and +8 Common associations. ALL t(9;22) t(4;11) Hyperdiploidy Hypodiploidy Ph translocation, poor prognosis. Poor prognosis. i total chromosome number \200\224good pr ognosis. d total chromosome number \200\224bad prognosis. T-ALL t(1;14) t(8;14) Involves tal-1 oncogene. B-ALL and Burkitt lymphoma t(8;14) Involves myc and IgH genes, poor prognosis. CLL +12, t(11;14) ATLL 14q11 NHL t(14;18) t(11;14) t(8;14) Follicular lymphoma, involves bcl-2 oncogene. Small cell lymphocytic lymphoma, involves bcl -1 oncogene. Burkitt lymphoma, involves myc and IgH genes. 756 CHAPTER 16 Hematological investigations Human leucocyte antigen (HLA) typing HLA system major histocompatibility complex (MHC) is t he name given to the highly polymorphic gene cluster region on human chromosome 6 which cod es for cell surface proteins involved in immune recognition. Box 16.1 The gene complex is subdivided into 2 regions The A, B, and C loci. Class 1 These proteins are found on most nucleated cells and interact with CD8+ T lymphocytes. Comprising of DR, DP, DQ loci present only on B lymphocytes, monocytes, macrophages and act ivated T lymphocytes. Interact with CD4+ T lymphocytes. Class 2 Class 1 and 2 genes are closely linked so one set of gene loci is usually inherited from each parent though there is a small amount of crossover. (See Box 16.1.) There is 71:4 chance of 2 siblings being HLA identical. \200 There are other histocompati bility loci apart from the HLA system but these appear less important generally except duri ng HLA matched SCT when even diff erences in these minor systems may cause GvHD. Typing methods Class 1 and 2 antigens were originally defi ned by serological reactivity wi th maternal antisera containing pregnancy-induced HLA antibodies. Many problems with techni que and too insensitive to detect many poly- morphisms. Molecular techniques are increasing ly employed such as SSP. Molecular characterization is detecting vast class 2 polymorphism. Importance of HLA typing \200 Matching donor/recipient pairs for renal, cardiac, and marr ow SCT. \200 Degree of matching more critical for stem cell than solid organ transplants. Sibling HLA matched STC is now treatment of choice for many malignancies. Unrelated donor SCTs are increasingly performed but outcome is poorer due to HLA disparity. As molecular matching advances, improved accuracy will enable closer matches to be found a nd results should improve. Functional tests of donor/recipient compatibility. \200 Mixed lymphocyte culture (MLC) \200\224now rarely used. \200 Cytotoxic T lymphocyte precursor assays (CTLp) \200\224dete rmine the frequency of CTLs in the donor directed against the recipient \200\224 provides a n assessment of GvHD occurring. 757 HUMAN LEUCOCYTE ANTIGEN (HLA) TYPING HLA-related transfusion issues \200 HLA on WBC and platelets may cause immunization in re cipients of blood and platelet transfusions. May cause refractoriness and/or febrile reactions to platelet transfusions. WBC depletion of products by fi ltration prevents this. \200 Diagnosis of refractoriness confi rmed by detection of HLA or platelet specifi c antibodies in patient \200\231s serum. Platelet transfusions matched to recipient HLA type may improve increments. This page intentionally left blank 759 Chapter 17 Blood transfusion Introduction 760 Using the blood transfusion laboratory 762 Transfusion of red blood cells 764 Platelet transfusion 768 Fresh frozen plasma 770 Intravenous immunoglobulin 772 Transfu sion transmitted infections 774 Irradiated blood products 776 Strategies for reducing blood transfusion in surgery 777 Maximum surgical blood ordering schedule (MSBOS) 778 Patients r efusing blood transfusion for religious reasons, i.e. Jehovah \200\231s Witnesses 780 760 CHAPTER 17 Blood transfusion Introduction Transfusion medicine has changed dramatically with an increasing aware- ness o f the risks involved with blood transfusion and a greater evidence base supporting clinical transfusion practice. It has become apparent that lower thresholds of transfusion provide equal or even improve outcomes for patients. More and more guidelines are available that he lp guide the appropriate use of blood and components and these have also helped to improve safety of transfusion practice There are limited resources, as well as a rising demand for specifi c blood components and an ever more decreasing number of donors. If there are any questions about the administration of blood, or appropriateness of blood c omponents for individual patients contact a member of your hospital transfusion team (which includes the con- sultant hematologist responsible for transfusion, specialist transfusion practitioner and transfusion laboratory manager). Specialist transfusion advice from a con sultant hematologist in transfusion is also available via the National Blood Service (e.g. NHS Blood and Transplant in England). 761 INTRODUCTION 762 CHAPTER 17 Blood transfusion Using the blood transfusion laboratory Requests for group & save (blood-grouping) or cross- matching (compatibility testing) Transfusion samples are taken in an EDTA bottle (6mL) and must be signed by the person taking the sample thus vouching for the identity of the patien t. Both sample and request form must be clearly, legibly identifi ed with 3 points of ident ifi cation for the patient: name, date of birth, and hospital number. In emergencies where the identity and date of birth of the patient are not known, emergency numbers and wrist- b ands must be used. \200 In case of any discrepancies between sampling and request form th e sample will be discarded. Since errors related to having the \200\230wrong blood in tube \200\231 are relatively com mon with potential risk of ABO mismatched transfusions, the current British Committee for S tandards in Hematology (BCSH) guideline (2013) recommend that a 2nd sample should be reques ted for confi rmation of the blood group of any new patient, provided this does not impede the delivery of urgent red cells or components. \200 Clinical information including the i ndication for transfusion or time and date of surgery must be given. The majority of laboratories in the UK now use automated ABO and RhD blood grouping and red cell antibody testing with advanced information technology s ystems for documentation and reporting of results. Red cells that are ABO and RhD compatibl e can be provided using electronic issue (or \200\230computer cross-match \200\231), with no further testing needed, provided the patient does not have any antibodies and that there are robust automated systems in place for antibody testing and identifi cation of the pati ent. If a patient has red cell antibodies, electronic issue should not be used and red cell units negative for the relevant antigen (s) should be cross-matched for transfusion. For major elective surgery where the need for transfusion is likely, the transfusion laboratory should receive a group & save sample 7d prior to surgery so appr opriate blood can be made available (E see Maximum surgical blood ordering schedule, p.778) . In emergencies, unmatched group O blood must be available for immediate use if major hemorrhage with group O Rh (D) \210\222ve units in particular reser ved for women of childbearing age. For all patients a switch to ABO RhD compatible units sh ould be made as soon the blood group is known. Women of childbearing age should also receiv e K negative units to avoid the risk of forming anti-K antibodies. The ABO and RhD antigens are particularly important but there are many other antigens on red cells that may result in formation of antibodies following p regnancy or transfusion, such as Kell, other Rh antigens (c, C, E and e), Duff y antigens ( fya, fyb), Kidd antigens (jka, jkb), and these antibodies can cause delayed transfusion rea ctions or haemolytic disease of the newborn. 763 USING THE BLOOD TRANSFUSION LABORATORY Issue and administration of blood and blood products All hospitals must have a transfusion policy with clear guidance on correct patient identifi cation and the safe administration o f blood and components. Errors carry the potential for major morbidity or fatality. Patient s receiving a blood transfusion must wear an identifi cation band, with the minimum patient identifi ers including last name, fi rst name, date of birth, and unique patient number. P ositive patient identifi cation is essential at all stages of the blood transfusion process including blood sampling, collection of blood from storage and delivery to the clinical ar ea, and administration to the patient. \200 The prescription of blood must be made by a r egistered medical practitioner and the indication for and details of the product \200\231s administration must be recorded in the case record. Units of blood are issued for an individual patient and labeled accordingly. They must be collected from the transfusion laboratory or a blood fridge with appropriate check of the patient identity and taken to the clinical area where they will be used. Before administering, the patient \200\231s details and the unit of blood are rechecked by trained nursing staff at the bedside immediately prior to the transfusion. Any discrepancie s identifi ed must be referred urgently to the blood bank and the clinician responsible for the patient. Transfusion cannot proceed until any ambiguity about identity has been resolv ed. Blood products must be given within their expiry date. \200 Always check for damage to th e pack, discoloration, or any other visible abnormality. Administration of the red cell unit must commence within 30min after leaving the blood bank and be completed within 4h of commencing infusion. If a blood warmer needed, ensure a safe, approved warming procedure is used. No drug or other infusion solution should be added to any blood component. Blood can only be stored in specially designated, monitored refrigerators. Platelets should be used immediately and cannot be kept on the ward and must not be placed in a fridge. Administration of all blood components must be recorded in the case notes as well as documented on a special blood transfusion chart (usually part of the IV fl uid chart). The number of blood units or blood components given should be entered in the n otes. Each unit transfused must have \200\230traceability \200\231. So hospitals can trace the f ate of each unit of blood/blood component (including name and patient identifi cation). Thi s is as required by the Blood and Safety Qualifi cations that became UK law in 2005 based o n the EU blood directive on blood safety setting standards of quality and safety for the co llection, testing, processing, storage, and distribution of human blood and components. 764 CHAPTER 17 Blood transfusion Transfusion of red blood cells The Better Blood Transfusion \200\231s health service circul ars published in 1998, 2002, and 2007 provide strong recommendations for promoting safe tra nsfusion practice within hospitals, with particular emphasis on the appropriate use of bloo d and components in all clinical areas. All hospitals must have hospital transfusion committees (HTCs), with multidisciplinary repr esentation. These committees are responsible for overseeing implementation of guidelines, c linical audit, and training of all staff involved in transfusion. The HTC has an essential role within the hospital clinical governance framework and must be accountable to the chief executive. The hospital transfusion team, which comprises the transfusion nurse specialist, transfusio n laboratory manager, and consultant haematolo- gist in transfusion, undertakes various act ivities on a day-to-day basis to achieve the objectives of the HTC. Many of the the principles of the Better Blood Transfusion initiatives have now been encomp assed in patient blood management, an evi- dence-based, patient-focused initiative, involvi ng an integrated multidis- ciplinary team approach, with the aims of optimizing the patient \200\231s own blood volume (especially red cell mass), minimizing the patient \200\231s bl ood loss, and optimizing the patient \200\231s physiological tolerance of anemia, thereby r educing unnecessary transfusion. Valid consent for blood transfusion should be obtained and documented in the patient \200 \231s clinical record. Specifi c written consent for transfusion is not needed but patients must be informed of the indication for transfu- sion together with risks and benefi ts and alternatives available. Transfusion of red cells should only be given where there is a clear clin- ical indication with no alternatives available (see Table 17.1). Haematinic defi ciency (iron or B12 and fo late defi ciency) should be treated with replacement therapy rather than with transfusion. There has been a trend in favor of lowering the hemoglobin (Hb) threshold used as a \200 \230trigger \200\231 for red cell transfusion (e.g. Hb trigger of 7g or 8g/L for most patie nts with a threshold of 8g or 9g/L used if there is a history of cardiac disease). The initial assessment should include an evaluation of the patient \200\231s age, body weig ht, and any co-morbidity that can predispose to transfusion- associated circulatory overloa d, such as cardiac failure, renal impair- ment, or hypoalbuminaemia, and fl uid overload sh ould be considered when prescribing the volume and rate of transfusion. As a general guide, transfusing 1 unit of red cells gives an Hb increment of 1g/L but only if applied as an approximation for a 70 \200\22380kg patient. The use of single-unit transf usions in small, frail adults (or prescription in mL, as for pediatric practice) is recomme nded. \200 Red cells have a shelf life of 35d at 4 C and are supplied as concentrated red cells with a PCV between 0.55 and 0.75. Most units in the UK are supplied in \200\230optimal additive solution \200\231, SAGM, which allows removal of all the plasm a for preparation of other blood 765 TRANSFUSION OF RED BLOOD CELLS components and results in a less viscous product. The volume of a unit of concentrated cell s is 280 20mL. All blood in the UK is leucodepleted at source since 1999. \200 There may be additional \200\230special requirements \200\231 for some patients such as those with sickle cell dise ase, who are at very high risk of forming red cell alloantibodies, which i the risk of dela yed haemolytic transfusion reactions. Patients with haemoglobinopathy should therefore rece ive blood that is matched for the patient \200\231s full extended Rh type (c, C, D, Ee) and K type, to prevent their forming antibodies to these highly immunogenic antigens. Irradiated blood is needed for immunocompromised patients to reduce the risk of transfusion associated graft vs host disease. \200 Leucodepletion of blood components (other than gr anulocytes) provides adequate CMV risk reduction for most clinical situations, but CMV seronegative red cell and platelet components should be provided for intra-uterine transfusions and for neo nates, and for pregnant women requiring repeat elective transfusions during the course of p regnancy. Frozen RBCs are available at the National Blood Service. They are expensive to process, store, and handle and have a shorter shelf life after thawing. Clinic al usage is restricted to patients with extremely rare blood groups or with highly problema tic red cell allo-antibodies. \200 In autoimmune haemolytic disorders transfusion can be lifesaving as a short term support pending response to immunosuppression. Table 17.1 Indications for red cell transfusion Blood loss Acute hemorrhage, especially where >30% blood loss, e.g. following surgery, trauma, childbi rth, gastrointestinal bleed Bone marrow disorders causing anemia Myelodysplasia Hematological malignancies (e.g. acute leukemia, myeloma) BM fi brosis BM in fi ltration with secondary cancer Aplastic anemia Chemotherapy/radiotherapy or bone marrow transplantation \200 Homozygous -thalassaemia \200 Red cell aplasia \200 Hb SS (som e circumstances) \200 Autoimmune haemolytic anemia \200 Selected use in renal failure \200 Haemolytic disease of the newborn Inherited RBC disorders Acquired RBC disorders Neonatal and exchange transfusions 766 CHAPTER 17 Blood transfusion Monitoring \200 Monitoring of the patient involves recording temperature, pulse, O2-satur ation, and BP before transfusion, every 15min for the 1st hour and hourly until transfusion is fi nished. Adverse events should be meticulously recorded. \200 Major reactions require immediate ce ssation of the transfusion and instigation of a full investigative protocol (E see Transfusion reactions, p.638). Minor febrile reactions are not uncommon. Review by a registered medical practitioner is advised. Their occurrence should be recorded, simple measures such as slowing the rate of infusion or administration of an antihistamine may deal with the pro blem; if not, transfusion of the specifi c unit should be stopped. An RBC pack should be given within 30min of removal from the blood bank fridge. The target infusion time for an individual unit should be 4h. 767 TRANSFUSION OF RED BLOOD CELLS 768 CHAPTER 17 Blood transfusion Platelet transfusion Platelets are given to prevent or treat bleeding associated with throm - bocytopaenia. They may also be given as prophylaxis against bleeding e.g. in patients und ergoing intensive chemotherapy (see Table 17.2). Platelets may be required to cover surgery and dentistry. An adult therapeutic dose (ATD) or 1 unit of platelets can be produced either by single-don or apheresis or by centrifugation of whole blood fol- lowed by separation and pooling of th e platelet-rich layer from 4 dona- tions suspended in plasma. Platelets can be stored for 5d at 20 \200\22324 C with constant agitation to maintain opti mal platelet function. Bacterial screening of platelets before release can reduce the risk of bac- teriological co ntamination, with an extension of the shelf life of platelet units to 7d. Platelet components must not be placed in a refrigerator. \200 Guidelines state a general threshold for procedures with regards to a patient \200\231s platelet count. A platelet co unt of \211 50 \227 109/L is suffi cient for minor surgery and procedures such as lumbar punctures, biopsies (including liver biopsy), insertion and removal of central lines. For major surgery as well as neurosurgery and eye surgery a platelet count of \211 100 \227 109/L is recommended. Patients can tolerate low platelet counts very well and platelets should not be given if the patient is well with no signs of bleeding and a platelet count >10 \227 109/L. Table 17.2 Indications for platelet transfusion Acute and chronic leukaemias \200 Myelodysplasia \200 Myeloproliferative disorders and myelofi brosis \200 Marrow infi ltration with other malignant tumors \200 Post-chemothe rapy or TBI \200 Aplastic anemia \200 Hypersplenism 2 splenic infi ltration or portal d production due to BM failure/infi ltration i platelet destruction in peripheral circulation hypertension Consumptive coagulopathies e.g. DIC \200 Avoid in TTP \200 Acute and chronic ITP (in em ergencies only) \200 Alloimmune thrombocytopenias, e.g. PTP and perinatal thrombocytopenia (need to be HPA typed) Sepsis \200 Drug induced \200 Platelet count <50 x 109/L anticipated after 1.5 \200\223 2 x Massive blood transfusion blood volume replacement) Aim to maintain platelet count >75 \200\223109/L \200 Antiplatelet drugs and bleeding \200 Myelodysplasia \200 Rare congenital disorders, e.g. Bernard \200\223Soulier Platelet function abnormalities 769 PLATELET TRANSFUSION In certain conditions, such as MDS or ITP, even platelet counts in single fi gures are acceptable as long as there are no clinical signs of bleeding. Where there is high consumption of platelets, i.e. bleeding, infection, or DIC, further doses of platelets might be needed to achieve haemostasis. Even in immune causes of thrombocytopaenia where routinely platelet transfusions are not indicated, platelet transfusions should be given in the acute event of a life-threatening bleed to try and achieve haemostasis. Platelet refractoriness is defi ned as failure to increment more than 10 \227 109/L after 2 separate transfusions of random platelets. It is very important to follow-up further tran sfusions with increments so the diagnosis can be confi rmed and management optimized. Both immune and non-immune causes should be considered: Non-immune: old low-dose platelets, high consumption (DIC, bleeding), hepatosplenomegaly, d rug-induced (amphotericin, AmBisome, vancomycin, heparin, and others). Immune: class-I HLA antibodies or HPA-antibodies. HLA-matched should be given if HLA antibodies are suspected. \200 Platelets are all leucodepleted at source since 1999. \200 Group ABO matched platelets are preferred. Do not give group O pl atelets to group A, B, or AB patients, unless they have been tested \210\222ve for high ti tre antibodies (HTO). Indications for irradiated and CMV \210\222ve products are the same as for red cell transfusions. \200\230Washed platelets \200\231: platelets in additive solution (plasma extracted and additive added) may be needed for patients with severe allergic reactions. They only ha ve a 24h shelf life. 770 CHAPTER 17 Blood transfusion Fresh frozen plasma FFP is produced by separation and freezing of plasma at \210\22230 C. As a vCJD reduction step, single donation units sourced outside the UK, treated with methy lene blue to reduce microbial activity, are indicated for all children born after 1996. Sol vent-detergent plasma is prepared commercially from pools of 300 \200\2235000 plasma donati ons that have been sourced from non-UK donors and treated with solvent and detergent to red uce the risk of viral transmission. (See Tables 17.3 and 17.4.) FFP is ABO grouped. Rh (D) grouping is not needed. Irradiation is not required. Table 17.3 Composition of FFP Factor II VII IX X Range (U/dL) 53 \200\223121 41 \200\223140 32 \200\223102 61 \200\223150 Median 82.5 92.0 61.0 90.5 Indications for use \200 Prothrombin complex concentrate and not FFP should be used for r eversal of warfarin anticoagulation (E see Warfarin overdosage, p.656).