Blood Transfusion

Questions and Answers

What is the minimum weight requirement for blood donors?

50 kg (correct)

55 kg

45 kg

60 kg

What is the maximum age limit for new blood donors?

60 years

63 years

61 years (correct)

65 years

What is the required hemoglobin level for male blood donors?

125 g/l

135 g/l (correct)

140 g/l

130 g/l

What is the minimum donation interval for whole blood donation?

12 weeks Signup and view all the answers

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

Cardiovascular disease Signup and view all the answers

Which behavior is considered high-risk for blood transfusion safety?

Intravenous drug use Signup and view all the answers

What chronic infection is a concern for blood transfusion recipients?

Hepatitis C Signup and view all the answers

What activity might pose a risk for blood transfusion recipients due to possible bloodborne infections?

Tattooing Signup and view all the answers

What is the primary use of Human IgG obtained from donors with high levels of specific antibodies?

For passive immunization against specific pathogens Signup and view all the answers

What is the role of Human Albumin in medical treatments?

Restoration of circulating blood volume Signup and view all the answers

What determines each blood group system?

Single genetic locus or closely linked loci Signup and view all the answers

Which antigens are found in the Rh blood group system?

D, E, e, C, c Signup and view all the answers

What is the primary reason for running blood through a white cell filter during the transfusion process?

To limit the risk of transmission of prions Signup and view all the answers

Which blood type corresponds to the antigen profile: B RhD pos, C+c+E-e+ K-k+ M+N+ S+s+ Fya+b- and Jka-b+?

B Blood Type Signup and view all the answers

What is the primary function of transferase enzymes in the ABO blood group system?

To add sugars to the A and B antigens Signup and view all the answers

What is the maximum shelf life of concentrated red cells at 4°C?

35 days Signup and view all the answers

What can lead to the acquisition of B antigen in individuals?

Rectal and bowel carcinomas Signup and view all the answers

Why must plasma be frozen within 4 hours of donation?

To preserve the clotting factors which are labile Signup and view all the answers

What is the purpose of platelet transfusions?

To prevent and treat hemorrhage in thrombocytopenia Signup and view all the answers

Which gene is necessary for the expression of A and B antigens in the ABO blood group system?

H (FUT1) gene Signup and view all the answers

What describes the Oh phenotype regarding blood group typing?

Individuals produce no H substance Signup and view all the answers

What is apheresis used for in blood donation?

To collect specific blood components like platelets Signup and view all the answers

What is the significance of recent travel to areas with endemic infectious diseases for blood transfusion recipients?

It increases the risk of transfusion-transmitted infections Signup and view all the answers

What is a common misconception about Group O individuals?

They have the highest incidence of thromboembolic disease Signup and view all the answers

What is the typical storage condition for platelet concentrate?

At room temperature with agitation Signup and view all the answers

What is the most significant health concern related to the transfusion of blood from donors with known infectious diseases?

Transmission of infections through the transfusion Signup and view all the answers

What is the importance of determining ABO and Rh type in blood donation?

It ensures compatibility during transfusions Signup and view all the answers

Why is Human Immunoglobulin used in medical treatments?

To replace missing antibodies in patients Signup and view all the answers

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

They have a naturally occurring anti-H antibody. Signup and view all the answers

What is the location of the RH locus?

Chromosome 1 Signup and view all the answers

What are the antithetical alleles in the Kell system?

K and k Signup and view all the answers

What defines Rhnull individuals?

They fail to produce RhD and RhCE proteins. Signup and view all the answers

What is the common symptom associated with individuals who have Rhnull?

Chronic mild hemolytic anemia Signup and view all the answers

What is the shared feature of the genes that comprise the Rh blood group system?

They are highly homologous and closely linked. Signup and view all the answers

What is X-Linked McLeod Syndrome characterized by?

Lack of Kx, leading to decreased Kell antigens. Signup and view all the answers

What are the two alleles in the FY system?

Fya and Fyb Signup and view all the answers

How do Fya and Fyb antigens differ?

By a single amino acid at position 44 Signup and view all the answers

What types of antibodies can individuals with Oh phenotype produce?

Anti-H antibodies Signup and view all the answers

What is the role of the XK locus in Kell protein expression?

Producing Kx protein for Kell protein expression Signup and view all the answers

What is the primary role of the Fy glycoprotein?

Acting as a receptor for proinflammatory chemokines Signup and view all the answers

What is the phenotype frequency of the Duffy a-b- group in Caucasians?

Completely absent Signup and view all the answers

How are Rhnull cells described morphologically and functionally?

Morphologically abnormal (stomatocytosis) and functionally abnormal (increased cation transport) Signup and view all the answers

Which gene at the FY locus is responsible for the Fy(a-b-) phenotype?

Fy Signup and view all the answers

What mutation occurs in the Fy gene compared to Fyb?

A mutation in the promoter region Signup and view all the answers

What characterizes the Jka-b- phenotype?

Defective urea transport in individuals Signup and view all the answers

Which proteins do GYPA and GYPB genes encode?

Glycophorin A and B Signup and view all the answers

How are naturally occurring red cell antibodies characterized?

Present without prior exposure to foreign antigens Signup and view all the answers

What types of antibodies can red cell antibodies be classified into?

IgM or IgG Signup and view all the answers

What role does Doppler ultrasound play in monitoring fetal health?

It can monitor for signs of fetal anaemia. Signup and view all the answers

Which technique is used for genotyping the fetus?

Genotyping from maternal blood samples Signup and view all the answers

What intervention may be performed if a fetus is severely affected by anaemia?

Intra Uterine Transfusion Signup and view all the answers

What are the platelet-specific antibodies associated with Neonatal Alloimmune Thrombocytopenia (NAIT)?

Maternal antibodies to HPA-1a and HPA-5b Signup and view all the answers

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

10% Signup and view all the answers

Which treatment may be necessary for a newborn with very high bilirubin levels?

Exchange transfusions via the umbilical vein Signup and view all the answers

What blood type is considered the universal donor?

Group O Signup and view all the answers

During an intravascular haemolytic transfusion reaction, what component is released into the circulation?

Hemoglobin Signup and view all the answers

What symptoms might a patient experience during an intravascular haemolytic transfusion reaction?

Fever and chills Signup and view all the answers

What interaction changes occur during an extravascular haemolytic transfusion reaction?

IgG antibodies sensitize red blood cells Signup and view all the answers

What is a key complication that can arise from an intravascular haemolytic transfusion reaction?

Hypotension and shock Signup and view all the answers

What distinguishes a delayed extravascular haemolytic transfusion reaction?

Symptoms appearing 5-10 days after transfusion Signup and view all the answers

What is the cause of Hemolytic Disease of the Fetus and Newborn (HDFN)?

Antibodies derived from the mother Signup and view all the answers

What triggers the production of ABO antibodies in infants?

Environmental stimuli Signup and view all the answers

What is the mortality rate associated with delayed extravascular haemolytic transfusion reactions?

Low Signup and view all the answers

What happens to the hemoglobin level during a delayed extravascular haemolytic transfusion reaction?

It drops Signup and view all the answers

What is the most common cause of Hemolytic Disease of the Newborn (HDN)?

RhD incompatibility Signup and view all the answers

What should be performed during pregnancy booking to screen for Hemolytic Disease of the Newborn?

ABO typing, Rh D typing, and antibody screening Signup and view all the answers

When is anti-D immunoglobulin administered during Rh D negative pregnancies?

At 28 weeks gestation Signup and view all the answers

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

K negative Signup and view all the answers

What is the order of severity of the causes of Hemolytic Disease of the Newborn?

Anti-D, Anti-c, Anti-K, ABO antibodies Signup and view all the answers

What is necessary for transfusion-dependent patients?

They should have a full Rh phenotype match including C, c, E, and e Signup and view all the answers

What type of antibodies are anti-Jka antibodies classified as?

IgG3, complement-binding, and labile Signup and view all the answers

Which screening is repeated during pregnancy if no antibodies are detected at booking?

At 28 weeks gestation Signup and view all the answers

What test is performed on maternal blood post-delivery to detect fetal cells?

Kleihauer test Signup and view all the answers

What is one of the main clinical effects of Hemolytic Disease of the Newborn?

Kernicterus Signup and view all the answers

Study Notes

Blood Donation Requirements

Donors must weigh between 50kg and 158kg.
Age requirement is 17 to 65 years (61 for new donors).
Female donors need a hemoglobin (Hb) level of at least 125g/l; male donors need at least 135g/l.
Minimum donation interval is 12 weeks for whole blood and 16 weeks for double red cell donations.

Disqualifying Conditions for Blood Donation

Pregnant individuals or those with an infant under 12 months old are disqualified.
Individuals with cardiovascular diseases or those undergoing surgery or medical investigations cannot donate.
High-risk behaviors such as intravenous drug use and unprotected sex may disqualify donors.

High-Risk Infections and Risks

Chronic infections like HIV, hepatitis B, and hepatitis C pose risks for blood transfusion recipients.
Variant Creutzfeldt-Jakob disease (vCJD) poses a risk due to prion-associated diseases.
Previous blood transfusions may increase the risk of alloimmunization and transfusion reactions.
Recent travel to areas with endemic diseases elevates the risk of transfusion-transmitted infections.

Blood Processing and Storage

Blood is taken into closed plastic bags, with a white cell filter used to minimize prion transmission risk.
Blood is separated into components like red blood cells, platelets, and plasma through centrifugation.
Red cell concentrates are viable for 35 days at 4°C; platelets have a 5-day shelf life stored at 22°C.
Fresh Frozen Plasma must be frozen within 4 hours and can be stored for up to 2 years at -30°C.

Blood Components and Their Uses

Red cell transfusions are used for increasing oxygen delivery in anemia.
Platelet transfusions are indicated for patients with thrombocytopenia.
Fresh Frozen Plasma replaces clotting factors in specific situations.
Human Immunoglobulin is used for antibody deficiency syndromes and immunological disorders.

Blood Group Systems and Antigens

Blood groups consist of antigen systems defined by genetic loci and include ABO, Rh, Kell, MNS, Duffy, and Kidd systems.
ABO system antigens are A, B, and O; Rh system includes D, E, e, C, c, while the Kell system includes K and k.
Frequencies of blood groups vary among ethnic groups due to population isolation and historical pandemics.

Rh Blood Group System

The Rh locus is located on chromosome 1; Rh antigens are direct gene products from genes RHD and RHCE.
Rhnull individuals do not produce RhD or RhCE proteins, leading to chronic mild hemolytic anemia.

Inheritance and Phenotypes

ABO blood groups follow simple inheritance rules: O allele is recessive, while A and B are co-dominant.
Phenotype frequencies differ across populations, affecting malaria resistance, especially with Duffy and Rh systems.

Blood Antibodies

Naturally occurring antibodies target absent red cell antigens; immune antibodies arise from transfusion or pregnancy.
ABO group O individuals have anti-A and anti-B antibodies, while group AB has none, being the universal recipient.

Hemolytic Transfusion Reactions

Intravascular hemolytic reactions involve IgM activation, leading to hemoglobin release and serious symptoms like hypotension and shock.
Extravascular reactions involve IgG antibodies and macrophages, sensitizing red blood cells.

Macrophage Interaction with Red Cells

Macrophages bind sensitized red cells through Fc receptor sites, primarily interacting with IgG1 and IgG3 antibodies.
Following binding, red cells may be phagocytosed or lysed, leading to their destruction.

C3 Activation and Complement Response

C3 activation occurs on the red cell membrane, enhancing binding to complement receptors on macrophages and monocytes, facilitating cell clearance.

Monocyte Interaction with Red Cell-bound IgG

Interaction generates low levels of cytokines, contributing to the immune response.

Delayed Extravascular Hemolytic Transfusion Reaction

Symptoms develop 5-10 days post-transfusion, characterized by fever, chills, jaundice, and hemoglobinuria.
Hemoglobin levels decrease as transfused red blood cells are destroyed.
The mortality rate associated with this reaction is low.

Haemolytic Disease of the Fetus and Newborn (HDFN)

HDFN is caused by maternal antibodies that cross the placenta, leading to reduced lifespan of fetal red blood cells.
The disease starts during intrauterine life and can have serious outcomes if untreated.

Clinical Effects of HDFN

Common manifestations include anemia, hydrops fetalis, hyperbilirubinemia, neurological defects, kernicterus, and hepatosplenomegaly.

Transfusion Requirements

ABO and Rh D typing must be matched for transfusions.
K-negative blood is recommended for women of childbearing age.
Transfusion-dependent patients require full Rh phenotype matching, including D, C, c, E, and e antigens.

Antibodies to High-Frequency Antigens

Antibodies like anti-K can lead to acute transfusion reactions, requiring specific donor panel or frozen cells.

Anti-Jka Antibodies

Anti-Jka antibodies are IgG3 and are a common cause of severe delayed hemolytic transfusion reactions; they are labile in vivo and in vitro.

Pregnancy Screening for HDFN

Screening aims to identify at-risk pregnancies and plan treatments efficiently, including ABO typing, Rh D typing, and antibody screening at booking and 28 weeks gestation.

RhD Status Prediction

Cell-free fetal DNA testing predicts the RhD status of pregnancies in Rh D negative individuals with 95.7% accuracy.

Anti-D Immunoglobulin Administration

Administered to Rh D negative pregnant women at 28 weeks gestation and post-delivery if the infant is Rh D positive.

Detection of Fetal Cells in Maternal Blood

A maternal blood film examined via the Kleihauer test determines the presence of fetal cells post-delivery.

Severity Order of HDFN Causes

Causes ranked by severity include Anti-D, Anti-c, Anti-K, ABO antibodies, Anti-E, and Anti-Fya.

Antibody Monitoring in Pregnancy Complications

Monitor antibodies such as Anti-D (>4 iu/mL) and anti-c (>7.5 iu/mL) along with ultrasound for fetal health indicators.

Ultrasound and Doppler Monitoring

Ultrasound assesses fetal growth, hydrops, and hepatosplenomegaly, while Doppler ultrasound detects signs of fetal anemia.

Intrauterine and Postnatal Treatment

If affected fetus shows severe anemia, an intrauterine transfusion may occur, with immediate UV phototherapy or exchange transfusions post-delivery if bilirubin levels are high.

Neonatal Alloimmune Thrombocytopenia (NAIT)

Maternal antibodies against HPA-1a and HPA-5b are associated with NAIT, affecting 10% of HPA-1a negative women who produce antibodies; 30% of these may have an affected fetus with thrombocytopenia.

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Test your knowledge on the essential requirements for blood donors, including weight, age, hemoglobin levels, and donation intervals. This quiz covers the crucial guidelines that ensure safe blood donation practices.