5-RH Flashcards
(135 cards)
1
Q
What reagent is used in Rh grouping
A
anti-sera D
2
Q
What reagents are used in ABO grouping
A
anti-sera A+anti-sera B
3
Q
What procedures are performed simultaneously in the laboratory
A
Rh grouping+ABO grouping
4
Q
What is the purpose of Rh grouping procedure
A
detection of D antigen on red cells
5
Q
What does Rh grouping detect
A
presence or absence of D antigen
6
Q
What does Rh grouping determine on red cell surface
A
attachment of D antigen
7
Q
What is the second most important blood group system after ABO in transfusion medicine
A
Rh system
8
Q
What disease is linked to the discovery of the Rh system
A
erythroblastosis fetalis
9
Q
What blood group system is most important in transfusion medicine
A
ABO system
10
Q
What blood group system addresses hemolytic transfusion reaction despite ABO compatibility
A
Rh blood group system
11
Q
What is the immunogenic antigen in the Rh system
A
D antigen
12
Q
What does immunogenic mean
A
ability to stimulate immune response
13
Q
What antibody is produced by Rh negative individuals exposed to D antigen
A
anti-D antibody
14
Q
What happens when Rh negative recipient receives Rh positive blood
A
production of anti-D antibodies
15
Q
What is better to transfuse to an Rh positive individual
A
Rh negative blood
16
Q
Why is Rh negative blood preferred for Rh positive recipients
A
lacks D antigen
17
Q
List equipment needed for Rh grouping
A
centrifuge+micropipette+microscope+test tube rack
18
Q
What glassware is used in Rh grouping
A
test tubes
19
Q
What reagents are used in Rh grouping
A
anti-sera D+0.9% saline
20
Q
What types of samples are used for Rh grouping
A
clotted blood+EDTA blood
21
Q
What miscellaneous materials are needed
A
marker+ballpoint pen+blood typing worksheet
22
Q
What indicates a positive Rh grouping test
A
agglutination with anti-D reagent
23
Q
What does absence of agglutination indicate initially
A
negative test result for D antigen
24
Q
What must be done if no agglutination occurs
A
perform additional tests for weak D phenotype
25
What materials are prepared for test tube setup
test tubes+racks+pipettes+anti-sera D+centrifuge+incubator
26
What were early Rh reagents
polyclonal IgG recognizing many epitopes
27
What was a problem with high-protein additives in reagents
spontaneous agglutination
28
When were monoclonal reagents developed
1980s
29
What is limitation of monoclonal reagents
react to single D epitopes missing some positives
30
What are most current Rh reagents
monoclonal blends of varying clones
31
What is monoclonal antibody production
fusion of antibody-producing cells with myeloma cells forming hybridomas
32
What do hybridomas produce
large quantities of monoclonal antibodies
33
Why combine multiple monoclonal antibodies in blends
detect wider range of Rh D-positive variants
34
What is the structure of D antigen
multiple epitopes
35
What does a single monoclonal antibody target
one specific epitope
36
What antibodies are combined in anti-D reagent
IgM+IgG monoclonal antibodies
37
What is function of IgM in anti-D reagent
visible agglutination in immediate spin phase
38
What is function of IgG in anti-D reagent
detection of weak D antigens via indirect antiglobulin test (IAT)
39
What is the first step in Rh grouping procedure
label tubes with patient+unit+test identification
40
What concentration of red cell suspension is prepared for Rh grouping
3-5% red cell suspension
41
What reagent is added to each test tube in Rh grouping
one drop of anti-D reagent
42
What volume of cell suspension is added to each test tube in Rh grouping
one drop of 3-5% cell suspension
43
What is done after adding reagent and cell suspension in Rh grouping
mix well
44
At what speed and duration are tubes centrifuged in Rh grouping
3500 rpm for 15-20 seconds
45
What is examined after centrifugation in Rh grouping
agglutination of red cell button
46
What is done after examining agglutination in Rh grouping
grade and record test results
47
What is the first step in Weak D testing
place one drop of anti-D reagent on patient’s tube
48
What concentration of red cell suspension is used in Weak D testing
3-5% suspension in saline
49
What is the incubation condition for Weak D testing
30 minutes at 37°C
50
At what speed and duration are tubes centrifuged in Weak D testing
1000 rpm for 15-20 seconds
51
How is agglutination checked after centrifugation in Weak D testing
macroscopically and microscopically if no agglutination
52
What indicates a D-positive result in Weak D testing
strong agglutination in anti-D tube but not in control tube
53
What is done if Weak D test results are doubtful or no agglutination
wash cells 3-4 times with large volume NSS
54
What is done after final wash in Weak D testing
decant saline blot tube rims with gauze add 2 drops antihuman globulin reagent
55
What is done after adding antihuman globulin reagent in Weak D testing
mix gently centrifuge at 1000 rpm for 15-20 seconds
56
How is agglutination read after antiglobulin phase in Weak D testing
macroscopically under well-lit area and microscopically if no agglutination
57
What is reported if agglutination occurs after incubation in Rh grouping
Rh positive
58
What is reported if no agglutination occurs after antiglobulin phase in Weak D testing
Rh negative
59
What is the purpose of Weak D testing
determine if no agglutination is due to Weak D phenotype or absence of D antigen
60
Why are steps 1 and 2 skipped in laboratory Weak D testing
use same test sample from Rh grouping due to dual function monoclonal blended anti-D reagent
61
What is indicated by agglutination in Rh grouping observation
Rh positive
62
What is the next step if no agglutination is observed in Rh grouping
proceed with Weak D (Du) testing
63
What does agglutination indicate about D antigen presence
presence of D antigen on red blood cell surface
64
What should not be done if no agglutination is observed initially
do not immediately report as Rh negative
65
What is the grading scale for agglutination reactions
0 to 4+
66
What does 4+ agglutination indicate microscopically
one solid agglutinate clear background
67
What does 3+ agglutination indicate microscopically
several large agglutinates clear background
68
What does 2+ agglutination indicate microscopically
medium-sized agglutinates clear background
69
What does 1+ agglutination indicate microscopically
small agglutinates turbid background
70
What does +/- agglutination indicate microscopically
very small agglutinates turbid background
71
What does mf agglutination indicate microscopically
mixture of agglutinated and unagglutinated cells turbid background
72
What does 0 agglutination indicate microscopically
no agglutination turbid background
73
What must be documented to prevent discrepancies and errors in test results
interpretation of agglutination reaction
74
Does the time started and time ended affect test results
no
75
Why is time started and time ended documented
to monitor adherence to turnaround time
76
What disease is caused by Rh antibodies affecting fetus and newborn
Hemolytic Disease of the Fetus and Newborn (HDFN)
77
What type of antibodies cause severe HDFN
Rh antibodies
78
What antigen is involved in HDFN
D antigen
79
Which mothers are usually affected by HDFN
Rh negative mothers carrying Rh positive fetus
80
What happens in the first pregnancy of Rh negative mother with Rh positive fetus
fetus is unaffected
81
What happens in succeeding pregnancies with Rh incompatibility
severe complications leading to HDFN
82
Why do maternal antibodies cause fetal hemolysis
IgG antibodies cross placenta and bind fetal Rh positive RBCs
83
What are maternal antibodies against D antigen called
Anti-D antibodies
84
Why is Rh incompatibility more significant than ABO incompatibility in pregnancy
maternal IgG antibodies cross placenta
85
What is Rh-immune globulin
purified IgG anti-D given to D-negative women during pregnancy and after delivery
86
What causes Fetal Maternal Hemorrhage
break in placental barrier allowing fetal blood to enter maternal circulation
87
What is leaked into maternal circulation during Fetal Maternal Hemorrhage
fetal RBCs
88
Name three causes of placental barrier breakage
normal physiological causes+invasive prenatal procedures+medical and obstetrics intervention
89
List normal physiological causes of placental barrier breakage
labor and delivery+3rd trimester uterine contractions+cesarean section
90
Name invasive prenatal procedures causing placental breakage
amniocentesis+chorionic villi sampling
91
What medical interventions can cause placental barrier breakage
miscarriage+abortions
92
What happens when fetal hemorrhage occurs
fetal hemoglobin mixes with maternal blood activating maternal immune system
93
What is isoimmunization
mother develops anti-D antibodies against Rh positive fetal RBCs
94
How much fetal maternal hemorrhage is needed for isoimmunization
0.01 mL to 0.3 mL
95
What is Rh-immune globulin effective in preventing
RhD HDFN
96
When is Rh immunoglobulin administered to Rh negative mothers
during 28th week of gestation+within 72 hours after delivery+after abortion or miscarriage
97
What is the standard dose of Rh immunoglobulin
300 micrograms or 1500 IU (one full vial)
98
What volume of fetal blood does one vial of Rh immunoglobulin protect against
30 mL fetal whole blood or 15 mL fetal RBCs
99
How is the need for additional Rh immunoglobulin dose determined
tests to check if full vial is enough
100
What invasive prenatal care procedures can cause placental barrier leakage
chorionic villi sampling+amniocentesis
101
What occurs during delivery that can cause placental barrier breakage
physical disruption allowing fetal blood leakage
102
What happens during sensitization in Rh negative mother
exposure to fetal Rh positive blood leads to antibody production
103
What type of antibodies produced by mother cross placenta to affect fetus
IgG antibodies
104
What is the effect of maternal Rh antibodies on Rh positive fetus
attack on fetal red blood cells causing hemolytic disease
105
What is the purpose of the Fetal Bleed Screen or Rosette Test
qualitative screening for fetal Rh-positive RBCs in Rh-negative mother
106
What principle does the Rosette Test use
indicator Rh-positive red cells form rosettes around fetal cells microscopically
107
What does a negative Rosette Test result indicate
no or minimal fetal bleed requiring standard Rh immunoglobulin dose
108
What does a positive Rosette Test result indicate
significant fetal bleed requiring quantitative testing (Kleihauer-Betke Test)
109
How is the Rosette Test performed
incubate maternal Rh-negative blood with anti-D immunoglobulin then add enzyme-treated Rh-positive indicator cells
110
What forms rosettes in the Rosette Test
indicator cells binding Fc regions of anti-D sensitized fetal red cells
111
What does erythrocyte rosetting look like microscopically
fetal red cell surrounded by indicator cells resembling a flower
112
What is the purpose of the Kleihauer-Betke Test (KBT)
quantitative estimation of fetal blood volume in maternal circulation
113
What principle does the Kleihauer-Betke Test use
fetal hemoglobin resists acid elution while adult hemoglobin is removed
114
What happens to adult hemoglobin in KBT
removed by acid elution leaving pale or ghost cells
115
What happens to fetal hemoglobin in KBT
remains intact staining fetal cells bright pink
116
What is the procedure for KBT
prepare maternal blood smear flood with acid buffer wash stain count 2000 cells calculate fetal cell percentage
117
What color do fetal RBCs stain in KBT
bright pink or red
118
What color do maternal RBCs appear in KBT
ghost-like or pale
119
How is the volume of fetal blood in maternal circulation calculated
by percentage of fetal cells counted in KBT
120
What is the clinical indication for Rh immunoglobulin administration
prevention of Rh isoimmunization in Rh-negative mothers
121
When is prenatal Rh immunoglobulin typically administered
28 to 34 weeks gestation
122
When is postnatal Rh immunoglobulin administered
within 72 hours after delivery of Rh-positive infant
123
What doses of Rh immunoglobulin are recommended antenatally
625 IU at 28 and 34 weeks or single 1500 IU dose
124
How is Rh immunoglobulin administered
intramuscularly or intravenously depending on indication
125
What sensitizing events in early pregnancy require Rh immunoglobulin
miscarriage termination ectopic pregnancy molar pregnancy chorionic villus sampling
126
What is the dose of Rh immunoglobulin recommended for sensitizing events in first 12 weeks
250 IU
127
What is the standard dose of Rh immunoglobulin after delivery
625 IU
128
What is the conversion between micrograms and international units for Rh immunoglobulin
1 microgram equals 5 IU
129
What is the rationale for Rh immunoglobulin administration
prevent maternal anti-D antibody formation after fetal-maternal hemorrhage
130
What is the significance of fetal-maternal hemorrhage
fetal Rh-positive RBCs enter maternal circulation triggering immune response
131
What testing is done to determine need for additional Rh immunoglobulin dose
fetal bleed screen (Rosette Test) and Kleihauer-Betke Test
132
What is the effect of Rh immunoglobulin on sensitization rates
reduces Rh(D) sensitization significantly
133
What is the half-life of Rh immunoglobulin in serum
approximately 24 days
134
What is the importance of timing in Rh immunoglobulin administration
within 72 hours of exposure to Rh-positive RBCs for effectiveness
135
What is the clinical guideline for Rh immunoglobulin use in Rh-negative pregnant women
routine antenatal and postnatal immunoprophylaxis unless fetus predicted Rh-negative
