Transfusion Science
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Questions and Answers

What is the minimum weight requirement for blood donors?

  • 45 kg
  • 50 kg (correct)
  • 170 kg
  • 65 kg

    • What is the age limit for new blood donors?

  • 17 years old
  • 61 years old (correct)
  • 50 years old
  • 70 years old

    • What is the required hemoglobin level for male donors?

  • 120 g/l
  • 145 g/l
  • 135 g/l (correct)
  • 130 g/l

    • How long must a donor wait before making another whole blood donation?

    <p>12 weeks</p> Signup and view all the answers

    Which of the following conditions would disqualify a potential blood donor?

    <p>Cardiovascular disease</p> Signup and view all the answers

    Which of the following is a high-risk behavior affecting blood transfusion safety?

    <p>Intravenous drug use</p> Signup and view all the answers

    What risk is associated with previous blood transfusions for recipients?

    <p>Risk of alloimmunization</p> Signup and view all the answers

    Which activity related to body modification poses a risk for bloodborne infections?

    <p>Tattooing</p> Signup and view all the answers

    What is a potential treatment for a fetus that is too young to be delivered and has severe anaemia due to haemolysis?

    <p>Intra Uterine Transfusion</p> Signup and view all the answers

    What is the purpose of immediate UV phototherapy after delivery?

    <p>To reduce unconjugated bilirubin levels</p> Signup and view all the answers

    What percentage of HPA-1a negative women produce antibodies related to NAIT?

    <p>10%</p> Signup and view all the answers

    Which type of transfusion can be performed via the umbilical vein for high bilirubin levels in a newborn?

    <p>Exchange Transfusion</p> Signup and view all the answers

    What is the role of top-up transfusions for a neonate in the months following the delivery?

    <p>To treat maternal antibody effects until they disappear</p> Signup and view all the answers

    What are the direct gene products of the ABO blood group system?

    <p>Transferase enzymes</p> Signup and view all the answers

    What gene is required in addition to the ABO genes for the expression of A and B antigens?

    <p>H (FUT1) gene</p> Signup and view all the answers

    Individuals with A1 red cells express how much more antigen compared to those with A2?

    <p>Five times as much</p> Signup and view all the answers

    What condition can lead to the acquisition of B antigen?

    <p>Bowel carcinomas</p> Signup and view all the answers

    What is the Oh phenotype?

    <p>A phenotype that produces no H substance</p> Signup and view all the answers

    Why are individuals with the Oh phenotype incompatible with all ABO groups except Oh?

    <p>They have a naturally occurring anti-H antibody</p> Signup and view all the answers

    What are Rh antigens classified as?

    <p>Direct gene products</p> Signup and view all the answers

    What is the function of Rh proteins?

    <p>Structural components involved in ion transport</p> Signup and view all the answers

    What characterizes the Kell system?

    <p>It features antithetical alleles K and k</p> Signup and view all the answers

    What is X-Linked McLeod Syndrome characterized by?

    <p>Lack of Kell antigens</p> Signup and view all the answers

    How do Fya and Fyb antigens differ?

    <p>By their amino acid sequences</p> Signup and view all the answers

    What is the inheritance pattern of the ABO blood group system?

    <p>Simple inheritance with O being recessive</p> Signup and view all the answers

    How many possible Rh haplotypes are typically seen?

    <p>Eight</p> Signup and view all the answers

    In which population is RhD negativity primarily due to gene deletion?

    <p>Caucasians</p> Signup and view all the answers

    Where is the Fy glycoprotein expressed?

    <p>On vascular endothelial cells and Purkinje cells in the cerebellum</p> Signup and view all the answers

    What is one of the primary roles of the Fy glycoprotein?

    <p>Serve as a receptor for proinflammatory chemokines</p> Signup and view all the answers

    In which populations is the Fy(a-b-) phenotype most commonly found?

    <p>Black Africans and populations where malaria is endemic</p> Signup and view all the answers

    What happens when an individual is homozygous for the Fy gene?

    <p>No production of the Fy glycoprotein on red cells</p> Signup and view all the answers

    What are Jka and Jkb in the context of the JK blood group system?

    <p>Codominant alleles that differ by a single amino acid</p> Signup and view all the answers

    How do red cell antibodies typically target antigens?

    <p>They target antigens the recipient lacks in their own red blood cells</p> Signup and view all the answers

    What symptom may a patient experience during an intravascular haemolytic transfusion reaction?

    <p>Tight chest and pain at the infusion site</p> Signup and view all the answers

    Which of the following statements about ABO antibodies is correct?

    <p>Group O individuals have both anti-A and anti-B antibodies</p> Signup and view all the answers

    What is the Jka-b- phenotype associated with?

    <p>Defective urea transport and related to 'silent' alleles</p> Signup and view all the answers

    What major complication can arise from an intravascular haemolytic transfusion reaction?

    <p>Hypotension and shock</p> Signup and view all the answers

    Which immune system component primarily responds during an extravascular haemolytic transfusion reaction?

    <p>IgG antibodies</p> Signup and view all the answers

    What distinguishes the Fy gene from the Fya and Fyb genes?

    <p>It has a mutation in the promoter region.</p> Signup and view all the answers

    What is a characteristic feature of the MNS blood group system?

    <p>It exhibits many rare variants in addition to common antigens.</p> Signup and view all the answers

    What is the main purpose of running blood through a white cell filter during transfusion preparation?

    <p>To remove prions associated with BSE</p> Signup and view all the answers

    In what situation is fresh frozen plasma indicated?

    <p>For replacement of coagulation factors</p> Signup and view all the answers

    What is a potential concern for blood transfusion recipients regarding recent vaccination?

    <p>Potential interactions affecting safety</p> Signup and view all the answers

    What are the antigens present in the ABO blood group system?

    <p>A, B, O</p> Signup and view all the answers

    How is Human Immunoglobulin primarily used in medical treatment?

    <p>For replacement therapy in antibody deficiency syndromes</p> Signup and view all the answers

    What is the significance of blood component centrifugation during blood processing?

    <p>To separate blood into its usable components</p> Signup and view all the answers

    What is the indication for platelet transfusions?

    <p>To prevent hemorrhage in thrombocytopenia</p> Signup and view all the answers

    What specific antigens are found in the Rh blood group system?

    <p>D, E, e, C, c</p> Signup and view all the answers

    Why must fresh frozen plasma be frozen within 4 hours of collection?

    <p>To prevent coagulation factors from degrading</p> Signup and view all the answers

    How are platelets stored post-transfusion preparation?

    <p>At 22oC while on a rocker</p> Signup and view all the answers

    What is the role of Human Albumin in medical treatment?

    <p>For restoring and maintaining blood volume</p> Signup and view all the answers

    What does differential centrifugation achieve in the blood processing procedure?

    <p>Isolates specific blood components for treatment</p> Signup and view all the answers

    What distinguishes the Kidd blood group system?

    <p>Presence of Jka, Jkb antigens</p> Signup and view all the answers

    Which of the following is a potential effect of recent medication on blood transfusion safety?

    <p>Altered immune response</p> Signup and view all the answers

    What antibodies do macrophages bind with the greatest affinity on sensitized red cells?

    <p>IgG1 and IgG3</p> Signup and view all the answers

    What happens to red cells after they bind to macrophages?

    <p>They are phagocytosed or lysed.</p> Signup and view all the answers

    What is a defining characteristic of a delayed extravascular hemolytic transfusion reaction?

    <p>Symptoms appear 5-10 days after transfusion.</p> Signup and view all the answers

    What are potential outcomes of Haemolytic Disease of the Fetus and Newborn (HDFN)?

    <p>Neurological defects and hydrops foetalis.</p> Signup and view all the answers

    What is the recommended blood type for women of childbearing age?

    <p>K negative</p> Signup and view all the answers

    How does RhD status prediction occur for RhD negative individuals during pregnancy?

    <p>Through cell-free fetal DNA testing</p> Signup and view all the answers

    What is a consequence of interaction between monocytes and red cell-bound IgG?

    <p>Generation of low levels of cytokines.</p> Signup and view all the answers

    What should be monitored in antibody levels for potential pregnancy complications?

    <p>Anti-D and anti-c</p> Signup and view all the answers

    What is the main purpose of pregnancy screening for Haemolytic Disease of the Newborn (HDN)?

    <p>To identify fetuses at risk and plan treatment.</p> Signup and view all the answers

    When is the antibody screen repeated during pregnancy if no antibodies are detected at booking?

    <p>At 28 weeks gestation</p> Signup and view all the answers

    What happens post-delivery if the infant is Rh D positive in Rh D negative pregnancies?

    <p>Further anti-D immunoglobulin is given to the mother.</p> Signup and view all the answers

    What technique can be used for genotyping the fetus?

    <p>Foetal sampling from maternal blood samples</p> Signup and view all the answers

    What is notable about anti-Jka antibodies?

    <p>They are common and cause more severe DHTRs.</p> Signup and view all the answers

    What is the order of severity of Hemolytic Disease of the Newborn (HDN) causes?

    <p>Anti-D, Anti-c, Anti-K, ABO antibodies, Anti-E</p> Signup and view all the answers

    What is the maximum weight limit for blood donors?

    <p>158 kg</p> Signup and view all the answers

    What is the minimum hemoglobin requirement for female blood donors?

    <p>125 g/l</p> Signup and view all the answers

    How long must a donor wait before being eligible to donate again after a whole blood donation?

    <p>12 weeks</p> Signup and view all the answers

    Which of the following is considered a high-risk behavior that could impact blood transfusion safety?

    <p>Intravenous drug use</p> Signup and view all the answers

    Which chronic infection is NOT mentioned as a concern for blood transfusion safety?

    <p>Hepatitis A</p> Signup and view all the answers

    What is the risk associated with receiving previous blood transfusions?

    <p>Alloimmunization</p> Signup and view all the answers

    Which of the following conditions disqualifies a potential blood donor?

    <p>Recent surgery</p> Signup and view all the answers

    What risk is plausible from activities such as tattooing or piercing regarding blood transfusions?

    <p>Risk of bloodborne infections</p> Signup and view all the answers

    What condition can lead to a baby being delivered early to prevent further exposure to maternal antibodies?

    <p>Severe haemolysis in the fetus</p> Signup and view all the answers

    What is the common purpose of UV phototherapy immediately after delivery?

    <p>To reduce unconjugated bilirubin levels</p> Signup and view all the answers

    What percentage of HPA-1a negative women are likely to produce antibodies associated with NAIT?

    <p>10%</p> Signup and view all the answers

    Which type of transfusion may be required for a newborn with critically high bilirubin levels?

    <p>Exchange transfusion</p> Signup and view all the answers

    What type of blood may a neonate require for top-up transfusions until the acquired antibody is gone?

    <p>Antigen negative blood</p> Signup and view all the answers

    What are the indirect gene products of the ABO blood group system?

    <p>A and B antigens</p> Signup and view all the answers

    Which chromosome contains the ABO locus?

    <p>Chromosome 9</p> Signup and view all the answers

    What condition can lead to the development of the B antigen?

    <p>Rectal and bowel carcinomas</p> Signup and view all the answers

    How do individuals with the Oh phenotype typically type regarding ABO blood groups?

    <p>They type as group 'O'</p> Signup and view all the answers

    What is the inheritance pattern of the ABO blood group system?

    <p>Co-dominance with multiple alleles</p> Signup and view all the answers

    What causes the synonymous Oh phenotype related to blood types?

    <p>Lack of H substance</p> Signup and view all the answers

    What is the result of acute hemolytic reactions regarding RhD negative individuals?

    <p>Severe immune response</p> Signup and view all the answers

    The Rh blood group system consists of which two closely linked genes?

    <p>RHD and RHCE</p> Signup and view all the answers

    Which of the following is true about Rhnull individuals?

    <p>They lack both RhD and RhCE proteins.</p> Signup and view all the answers

    What are the antithetical alleles in the Kell system?

    <p>K and k</p> Signup and view all the answers

    What typically characterizes individuals with X-Linked McLeod Syndrome?

    <p>Absence of Kx protein</p> Signup and view all the answers

    What happens to Rhnull cells in terms of morphology and function?

    <p>They exhibit stomatocytosis and increased cation transport.</p> Signup and view all the answers

    What role does the XK locus play in the expression of Kell protein?

    <p>It produces the Kx protein necessary for Kell antigen expression.</p> Signup and view all the answers

    What characterizes a delayed extravascular haemolytic transfusion reaction?

    <p>Symptoms appear 5-10 days after transfusion.</p> Signup and view all the answers

    What is the outcome of interaction between monocytes and red cell-bound IgG?

    <p>Generation of low levels of cytokines.</p> Signup and view all the answers

    How is C3 activated during the reaction with sensitized red cells?

    <p>On the red cell membrane.</p> Signup and view all the answers

    What does Hemolytic Disease of the Fetus and Newborn (HDFN) primarily result from?

    <p>Placental transfer of maternal antibodies.</p> Signup and view all the answers

    What is the primary method used to predict RhD status in Rh D negative pregnancies?

    <p>Cell-free fetal DNA testing.</p> Signup and view all the answers

    What is the recommended blood type for women of childbearing age?

    <p>K negative.</p> Signup and view all the answers

    What is a common clinical effect of Hemolytic Disease of the Newborn (HDN)?

    <p>Neurological defects.</p> Signup and view all the answers

    What is the significance of conducting antibody screening during pregnancy?

    <p>To detect potential fetal risks from maternal antibodies.</p> Signup and view all the answers

    What is the potential outcome of untreated Hemolytic Disease of the Fetus and Newborn?

    <p>Significant mortality and morbidity.</p> Signup and view all the answers

    What is required for ABO and Rh D matching in blood transfusions?

    <p>Both ABO and Rh D matching.</p> Signup and view all the answers

    What is a notable feature of anti-Jka antibodies?

    <p>They are IgG3 and often become undetectable.</p> Signup and view all the answers

    What should be monitored regarding the partner’s phenotype/genotype during a pregnancy with potential conflicts?

    <p>Compatibility and potential risks to the fetus.</p> Signup and view all the answers

    What occurs post-delivery if an infant is Rh D positive in Rh D negative pregnancies?

    <p>Further anti-D immunoglobulin is given to the mother.</p> Signup and view all the answers

    What role does Doppler ultrasound play in monitoring during pregnancy?

    <p>Checking for signs of fetal anaemia.</p> Signup and view all the answers

    What is the significance of the Fy(a-b-) phenotype in populations where malaria is endemic?

    <p>It serves as a resistance mechanism against malaria parasites.</p> Signup and view all the answers

    What happens to red blood cells when an individual is homozygous for the Fy gene?

    <p>Glycoprotein is not produced on red cells.</p> Signup and view all the answers

    Which of the following functions does the Fy glycoprotein NOT perform?

    <p>Provides immunity against all forms of malaria.</p> Signup and view all the answers

    Where is the JK locus located?

    <p>Chromosome 18</p> Signup and view all the answers

    What characterizes the Jka-b- phenotype?

    <p>It arises from the inheritance of a silent allele or a dominant inhibitor gene.</p> Signup and view all the answers

    Which of the following is true regarding naturally occurring red cell antibodies?

    <p>They are present without prior exposure to foreign antigens.</p> Signup and view all the answers

    Which of the following describes a common characteristic of the MNS blood group system?

    <p>It has many rare variants in addition to common antigens.</p> Signup and view all the answers

    What is the role of C3a and C5a in an intravascular haemolytic transfusion reaction?

    <p>They act as potent anaphylotoxins causing proinflammatory effects.</p> Signup and view all the answers

    What is a severe complication of an intravascular haemolytic transfusion reaction?

    <p>Hypotension and shock.</p> Signup and view all the answers

    Which of the following statements regarding ABO antibodies is correct?

    <p>Group O individuals produce both anti-A and anti-B antibodies.</p> Signup and view all the answers

    What is the structural characteristic of the JK protein?

    <p>It is a multipass protein associated with urea transport.</p> Signup and view all the answers

    Which alleles are codominant in the JK blood group system?

    <p>Jka and Jkb</p> Signup and view all the answers

    What mechanism underlies the production of red cell antibodies?

    <p>They result from exposure to absent red cell antigen types.</p> Signup and view all the answers

    How do the Fya and Fyb antigens primarily differ?

    <p>They differ by one residue at position 44.</p> Signup and view all the answers

    What is the role of white cell filtration in blood transfusion preparation?

    <p>To limit the risk of transmitting prions</p> Signup and view all the answers

    Why is Human Immunoglobulin derived from donors with high antibody levels used?

    <p>For passive immunization against specific diseases</p> Signup and view all the answers

    What is the recommended storage condition for platelet concentrates?

    <p>22°C on a rocker</p> Signup and view all the answers

    Which of the following components is used for the replacement of coagulation factors?

    <p>Fresh frozen plasma</p> Signup and view all the answers

    What is the primary purpose of differential centrifugation during blood processing?

    <p>To segregate blood into its component parts</p> Signup and view all the answers

    What is the maximum shelf life for red cell concentrate stored at 4°C?

    <p>35 days</p> Signup and view all the answers

    What does the presence of the D antigen in the Rh blood group system signify?

    <p>The individual is Rh positive</p> Signup and view all the answers

    Platelet transfusions are primarily indicated for which of the following conditions?

    <p>Thrombocytopenia or platelet function defects</p> Signup and view all the answers

    What is a primary concern for blood transfusion recipients regarding recent vaccinations?

    <p>Potential interactions affecting immune response</p> Signup and view all the answers

    What is the consequence of not freezing fresh frozen plasma within 4 hours of collection?

    <p>Loss of coagulation factor activity</p> Signup and view all the answers

    What is Human Albumin used for within transfusion practices?

    <p>To restore and maintain blood volume</p> Signup and view all the answers

    Which blood group system introduces variations based on structural molecules on red cell surfaces?

    <p>All blood group systems</p> Signup and view all the answers

    What happens during apheresis regarding blood donation?

    <p>Platelets are concentrated and returned to the donor</p> Signup and view all the answers

    Which antigen system is associated with granulocytes?

    <p>HNA system</p> Signup and view all the answers

    Study Notes

    Blood Donation Requirements

    • Donors must weigh between 50 kg and 158 kg.
    • Age range for donors is 17 to 65 years (61 for new donors).
    • Female donors require hemoglobin levels of at least 125 g/l; male donors must have at least 135 g/l.
    • Minimum intervals between whole blood donations is 12 weeks; for double red cell donations, it is 16 weeks.

    Disqualifying Conditions for Donors

    • Pregnancy or having an infant younger than 12 months disqualifies potential donors.
    • A history of cardiovascular disease, surgical procedures, or ongoing medical investigations may also exclude individuals from donating.

    High-Risk Behaviors Impacting Donor Safety

    • Intravenous drug use, unprotected sex, and multiple sexual partners are considered high-risk behaviors.

    Chronic Infections of Concern

    • Infections such as HIV, hepatitis B, and hepatitis C may pose risks to blood transfusion recipients.

    Prion-Associated Diseases

    • There is a risk of diseases such as variant Creutzfeldt-Jakob disease (vCJD) from prion transmission through blood.

    Previous Blood Transfusions

    • Past transfusions can increase the risk of alloimmunization and transfusion reactions.

    Concerns About Unknown or Viral Diseases

    • Diseases of unknown or viral etiology may transmit through blood, heightening risk for recipients.

    Risks from Body Modifications

    • Activities like piercing, tattooing, or acupuncture can enhance the likelihood of bloodborne infections.

    Travel Impact on Blood Safety

    • Travel to areas with endemic infections raises the risk of transmission for blood transfusion.

    Contact with Infectious Individuals

    • Exposure to infected persons can increase the risk of disease transmission through blood transfusion.

    Vaccination and Medication Effects

    • Recent vaccinations or medications may impact the safety of transfusions due to immune system interactions.

    Blood Collection and Processing System

    • Whole blood donation involves collecting 450 ml into a closed system, which is then filtered to remove white cells to mitigate prion risks.
    • Blood is separated into components using differential centrifugation for further processing.

    Blood Component Storage

    • Red cell concentrate is viable for 35 days at 4°C.
    • Platelets, made by pooling or apheresis, require storage at 22°C for up to 5 days.
    • Fresh Frozen Plasma must be frozen within 4 hours and can be stored for 2 years at -30°C.

    Indications for Blood Transfusion

    • Red cell transfusions are indicated for anemia-related oxygen delivery deficiencies.
    • Platelet transfusions are necessary for individuals with thrombocytopenia or platelet function defects.
    • Fresh Frozen Plasma is used for replacing coagulation factors in specific conditions.

    Human Immunoglobulin and Albumin

    • Human Immunoglobulin is utilized for antibody deficiency syndromes and passive immunization against pathogens.
    • Human Albumin aids in restoring and maintaining blood volume where deficiency is present.

    Blood Group Systems Overview

    • Blood group antigens are inherited, with key systems being ABO, Rh, Kell, MNS, Duffy, and Kidd.
    • Each system represents unique antigen configurations pivotal for blood type classification.

    ABO Blood Group System

    • Antigens include A, B and O; individuals with type O have anti-A and anti-B antibodies.
    • Frequency of blood groups varies across ethnic groups due to population migration and historical pandemics.

    Rh Blood Group System

    • The Rh locus is located on chromosome 1, detailing haplotypes like DCe, dCe, and their influence on blood typing.

    Kell and Duffy Blood Group Characteristics

    • The Kell system features antigens K and k, with 8% K+ and 99.8% k+ in the population.
    • Duffy antigens Fya and Fyb have implications for malaria resistance in endemic populations.

    Antibody Types and Their Functions

    • Naturally occurring antibodies are present without prior exposure; immune antibodies develop post-exposure.
    • Blood transfusions require careful matching to avoid hemolytic reactions.

    Hemolytic Transfusion Reactions

    • Intravascular reactions activate complement leading to cell lysis, while extravascular reactions involve IgG binding to red cells and subsequent macrophage removal.
    • Symptoms include fever, chills, and pain, with serious complications such as renal failure possible in severe cases.### Macrophages and Red Blood Cells Interaction
    • Macrophages bind sensitized red blood cells via Fc receptor sites, predominantly recognizing IgG1 and IgG3 antibodies.
    • Post-binding, red blood cells may undergo phagocytosis or lysis by macrophages.
    • C3 activation on red cell membranes facilitates binding to complement receptors on macrophages and monocytes, enabling rapid clearance of red cells.

    Monocyte Interaction and Immune Response

    • Interaction between monocytes and IgG-bound red cells results in low cytokine production.

    Delayed Extravascular Hemolytic Transfusion Reactions

    • Symptoms typically emerge 5-10 days post-transfusion.
    • Patients may experience fever, chills, jaundice, and hemoglobinuria.
    • Hemoglobin levels decrease as transfused red blood cells are destroyed.
    • The mortality rate for this reaction is low.

    Haemolytic Disease of the Fetus and Newborn (HDFN)

    • HDFN occurs when maternal antibodies shorten the lifespan of the infant's red blood cells via placental transfer.
    • The condition begins during intrauterine life and can result in significant morbidity and mortality if untreated.

    Clinical Effects of HDFN

    • Key clinical manifestations include:
      • Anemia
      • Hydrops fetalis
      • Hyperbilirubinemia
      • Neurological defects
      • Kernicterus
      • Hepatosplenomegaly

    Blood Group Matching and Transfusion Guidelines

    • ABO and Rh D matching is essential for safe transfusions.
    • Women of childbearing age should ideally receive K negative blood.
    • Transfusion-dependent patients require a full Rh phenotype match, including C, c, E, and e antigens.
    • If antibodies form, other antigens should be negative based on serological crossmatch.

    Specific Antibodies and Risks

    • Anti-Jka antibodies are IgG3, complement-binding, and can lead to severe delayed hemolytic transfusion reactions.
    • Individuals with antibodies to high-frequency antigens, such as anti-K, may encounter acute transfusion issues requiring special donor panels.

    Pregnancy Screening for HDN

    • Screening targets include ABO typing, Rh D typing, and antibody screening during pregnancy.
    • If antibodies are absent at booking, screening is repeated at 28 weeks gestation.
    • Cell-free fetal DNA testing predicts RhD status for Rh D negative pregnancies with 95.7% accuracy.
    • Anti-D immunoglobulin is administered at 28 weeks for Rh D negative pregnancies and again post-delivery if the infant is Rh D positive.

    Monitoring and Management of HDN

    • Maternal blood is examined post-delivery with the Kleihauer test for fetal cells.
    • Severity of HDN causes is ranked: Anti-D > Anti-c > Anti-K > ABO antibodies > Anti-E > Anti-Fya.
    • Significant antibody levels to monitor include Anti-D (>4 iu/mL), anti-c (>7.5 iu/mL), and specificities with a titre >32.
    • Ultrasound monitoring focuses on fetal growth, hepatosplenomegaly, and hydrops, while Doppler ultrasound checks for signs of fetal anemia.

    Treatment Options for Affected Infants

    • Depending on the situation, treatment options may include intrauterine transfusion, immediate UV phototherapy post-delivery, or exchange transfusions if bilirubin levels are excessive.
    • Ongoing transfusions of antigen negative blood may be necessary until the maternal antibodies wane.

    Neonatal Alloimmune Thrombocytopenia (NAIT)

    • Associated with maternal antibodies to HPA-1a and HPA-5b.
    • Approximately 10% of HPA-1a negative women produce antibodies, with 30% of these having an affected fetus/neonate with a low platelet count.

    Blood Donation Requirements

    • Blood donors must weigh between 50 kg and 158 kg.
    • Eligible age range for donors is between 17 and 65 years old (61 for new donors).
    • Hemoglobin criteria: Female donors require a minimum of 125 g/l; Male donors require at least 135 g/l.
    • Minimum donation intervals: 12 weeks for whole blood; 16 weeks for double red cell donations.

    Disqualification Conditions

    • Donors cannot be pregnant or have an infant under 12 months.
    • Individuals with cardiovascular disease or those undergoing surgery or medical investigations are disqualified.
    • High-risk behaviors, such as intravenous drug use or unprotected sex, can disqualify potential donors.

    Chronic Infections and Risks

    • Chronic infections like HIV, hepatitis B, and hepatitis C can affect blood transfusion safety.
    • Prion-associated diseases, such as variant Creutzfeldt-Jakob disease (vCJD), pose risks for recipients.
    • Previous blood transfusions may increase risks of alloimmunization and transfusion reactions.

    Effects of Body Modifications and Travel

    • Activities related to body modification (piercings, tattoos, acupuncture) might elevate the risk for bloodborne infections.
    • Recent travel to endemic areas raises risks of transfusion-transmitted infections.
    • Contact with infectious disease carriers could increase the chance of transmission through blood transfusions.

    Vaccination, Medications, and Blood Safety

    • Recent vaccinations or medications may impact the safety of transfusions due to potential immune effects or interactions.

    Blood Collection and Processing

    • Whole blood is collected into a closed system, filtered to remove white cells due to potential prion contamination.
    • Blood is separated into components: red cells, platelets, and plasma using centrifugation techniques.
    • Concentrated red cells maintain viability for 35 days at 4°C; platelets require storage at 22°C for up to 5 days.
    • Fresh frozen plasma must be frozen within 4 hours and can be stored for up to 2 years at -30°C.

    Blood Component Transfusions

    • Red cell transfusions are indicated for anemia-related oxygen delivery issues.
    • Platelet transfusions help prevent and treat hemorrhage in thrombocytopenic patients.
    • Fresh frozen plasma is used for coagulation factor replacement in specific scenarios.

    Human Immunoglobulin and Its Uses

    • Human IgG provides replacement therapy for antibody deficiency syndromes and is used for passive immunization against specific pathogens.
    • Human Albumin is critical for restoring and maintaining circulating blood volume.

    Blood Groups and Antigens

    • Blood group antigens are defined by genetic loci, including ABO, Rh, Kell, MNS, Duffy, and Kidd systems.
    • ABO blood group antigens include A, B, and O types connected to specific transferase enzymes.
    • Rh blood group includes D, E, e, C, and c antigens produced by genes RHD and RHCE on chromosome 1.

    Genetic Traits and Conditions

    • The presence or absence of blood group antigens is inherited in a Mendelian fashion.
    • Individuals with the Oh phenotype do not produce H substance, making them compatible only with Oh blood.
    • Kell antigens are encoded by KEL locus alleles, while Duffy system alleles affect susceptibility to malaria.

    Antibodies and Immune Response

    • Naturally occurring antibodies exist against red cell antigens not previously encountered.
    • ABO antibodies are directed against A and B antigens, impacting transfusion compatibility.
    • Intravascular and extravascular hemolytic transfusion reactions are severe responses that involve different antibody interactions, leading to significant physiological effects.

    Hemolytic Reactions

    • Intravascular reactions are mediated by IgM antibodies, activating the complement cascade.
    • Extravascular reactions involve IgG antibodies, leading to sensitization and clearance by macrophages.
    • Symptoms of intravascular reactions can include fever, chills, and lower back pain, with potential complications like renal failure and shock.### Macrophage Interaction with Red Cells
    • Macrophages bind sensitized red cells through Fc receptor sites, favoring IgG1 and IgG3 antibodies.
    • Following binding, red cells may undergo phagocytosis or lysis.

    C3 Activation

    • C3 activation on the red cell membrane allows binding to complement receptors (C1, C3) on macrophages/monocytes.
    • This interaction facilitates rapid clearance of red blood cells.

    Monocyte and IgG Interaction

    • Monocytes interacting with red cell-bound IgG produce low levels of cytokines.

    Delayed Extravascular Hemolytic Transfusion Reaction

    • Symptoms manifest 5-10 days post-transfusion.
    • Patients may experience fever, chills, jaundice, and hemoglobinuria.
    • Hemoglobin levels decrease as transfused red blood cells are destroyed.
    • Mortality rate for this reaction is low.

    Hemolytic Disease of the Fetus and Newborn (HDFN)

    • HDFN is caused by maternal antibodies transferring across the placenta, shortening fetal red blood cell lifespan.
    • The condition can begin during intrauterine life and may lead to significant mortality and morbidity without intervention.

    Clinical Effects of HDFN

    • Potential outcomes include anemia, hydrops fetalis, hyperbilirubinemia, neurological defects, kernicterus, and hepatosplenomegaly.

    ABO and Rh D Matching for Transfusions

    • ABO and Rh D must be matched prior to transfusions to avoid complications.
    • K negative blood type is recommended for women of childbearing age.
    • Transfusion-dependent patients require a full Rh phenotype match, including antigens C, c, E, and e.

    Antibody Considerations in Transfusions

    • Antigens should match according to serological crossmatch in cases of antibody production.
    • O negative blood is used for O negative patients but may contain other red cell antigens.

    Anti-K Antibodies and Anti-Jka Antibodies

    • Individuals with antibodies to high-frequency antigens like anti-K might require specific donor panels for transfusions.
    • Anti-Jka antibodies, which are IgG3 and complement-binding, can lead to severe delayed hemolytic transfusion reactions.

    Screening for Hemolytic Disease of the Newborn (HDN)

    • Aim is to identify fetuses at risk, predict severity, and guide treatment.
    • Initial screenings include ABO typing, Rh D typing, and antibody screening at booking.
    • Antibody screening is repeated at 28 weeks if no antibodies are found initially.

    Monitoring and Treatment in Rh D Negative Pregnancies

    • Cell-free fetal DNA testing is utilized to predict RhD status with high accuracy.
    • Anti-D immunoglobulin is administered intramuscularly at 28 weeks gestation.
    • Post-delivery, anti-D is given to the mother if the baby is Rh D positive.

    Detection of Fetal Cells

    • Maternal blood tests following delivery, such as the Kleihauer test, help identify fetal cells.

    Severity Ranking of HDN Causes

    • Causes of HDN by severity: Anti-D > Anti-c > Anti-K > ABO antibodies > Anti-E > Anti-Fya.

    Monitoring and Ultrasound in Pregnancy Complications

    • Antibody levels in pregnancies should be monitored; certain thresholds indicate increased risk.
    • Partner's genotype/phenotype compatibility is crucial for assessing fetal risk.
    • Ultrasound monitoring focuses on growth, hepatosplenomegaly, and hydrops.
    • Doppler ultrasound aids in detecting fetal anemia.

    Management of Affected Infants

    • Infants may undergo intrauterine transfusions or early deliveries if severely affected.
    • Immediate phototherapy post-delivery helps reduce hyperbilirubinemia.
    • Exchange transfusions may be necessary for extreme bilirubin levels and to manage ongoing hemolysis.

    Neonatal Alloimmune Thrombocytopenia (NAIT)

    • Maternal antibodies against HPA-1a and HPA-5b are linked to NAIT.
    • 10% of HPA-1a negative women produce antibodies; 30% of their fetuses may be affected with low platelet counts.

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    Test your knowledge about the key requirements for blood donors, including weight, age, hemoglobin levels, and donation intervals. This quiz will help you understand the essential criteria needed to volunteer as a blood donor effectively.

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