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sbb final Exam|98 Complete Questionsand Answers|100% Correct
A peripheral smear with increased polychromasia, schistocytes and
spherocytes is indicative of which condition?
A. Aplastic anemia
B. Iron deficiency anemia
C. Hemolytic anemia
D. Megaloblastic anemia - -C. Hemolytic anemia
Megaloblastic anemia would show larger, less mature RBCs on the smear.
Iron deficiency anemia would show hypochromasia, and a lower RBC count.
Aplastic anemia would show very little amounts of mature RBCs on the
smear
Hemolytic anemia results in misshapen RBCs and inconsistent RBC
appearance because of the rapid RBC destruction. Because the RBCs have as
shortened survival, pieces of the membrance can break off resulting in
spherocytes and schistocytes.
-Which of the following treatments is useful when distinguishing between
anti-D and anti-Lw?
A. Choloroquine
B. Cord cells
C. Ficin
D. Dithiothreitol - -Answer: Dithiothreitol (DTT)
LW antigens require divalent cations (e.g., Mg2+) for expression and have
intramolecular disulfide bonds that are sensitive to dithiothreitol (DTT)
treatment.
DTT treatment is helpful to differentiate anti-LW from anti-D, because the D
antigen is resistant to DTT while LW antigen is sensitive to DTT.
LW antigens are expressed equally well on group O D-positive and D-
negative cord blood red cell.
expected reaction with O- cord RBCsexpected reaction with O+ DTT treated
RBCsanti-LW+-anti-D-+
The best answer is DTT.
Cord cells are not considered a treatment and often used in conjunction with
DTT results to confirm the presence of either antibody.
ficin (breaks down proteins) and chloroquine (dissociates bound antibody
from RBCs/ destroys HLA antigens) do not disrupt disulfide bonds.
,-Therapeutic plasma exchange is most useful in treating patients with:
A. Circulating immune complexes
B. Autoimmune diseases
C. high titer IgG anti-D
D. Hyperimmune synromes - -Correct: Circulating Immune Complexes
Plasma exchange is used to help a temporary condition. So an autoimmune
disease is better treated with the use of steroids and other medicines that
will suppress the autoantibody production.
A patient with high titer anti-D is actively producing anti-D. So these patients
will also not benefit from plasma exchange since their immune system is just
going to produce more anti-D.
Patients with hyperimmune syndromes are also actively producing harmful
substances, so removing them won't be effective since more will be
produced as soon as the procedure is completed.
Circulating immune complexes are a condition that is caused by antigen-
antibody reaction due to a short lived condition, so the use of plasma
exchange is very effective in removing those large complexes. With
additional treatment, we can prevent more immune complexes from forming
so once the exchange is complete, the condition is most often resolved.
-Which of the following donors is eligible to donate?
A. Wife of a patient with active Hepatitis ; they are living together; last
sexual contact was 18 months ago.
B. Former prostitute; married with no high-risk behavior for 10 years
C. Male who had sex with another male 11 months ago
D. Male jailed for 7 days, 15 months ago - -Correct: Male jailed for 7 days, 15
months ago
AABB standards (32nd ed):
Incarceration for more than 72 consecutive hours defers the donor for 12
months from the date of release. Because this donor was released 15
months ago, he is eligible.
A person living with an individual with active Hepatitis is deferred. There
would also be deferral for 12 months from the date of the last sexual
contact. Once the infection is no longer present, the donor is eligible 12
months from the date the spouse's infection is deemed as no longer present.
Potential donors who have taken money or drugs for sex since 1977 are
indefinitely deferred.
Males who have had sexual relations with other males are deferred for 12
months after the last date of sexual contact. (recently changed due to
COVID-19, however ASCP is currently using pre-pandemic donor
requirements!)
, -A Native American woman who is group A Positive delivered a group O Rh
positive infant. The baby was noted to be jaundiced 6 hours after birth and
had a 3+ DAT. The mother's antibody screen had been negative before
delivery and an eluate prepared from the infant's cells was also non-reactive
with a routine antibody ID panel, A1 and B cells.
Which of the following cells should be tested to possibly assist in
identification of the antibody?
A. Doa
B. Dia
C. Cha
D, Coa - -Correct: Dia
The clues here are as follows: You want to look for an antibody that is
capable of causing a significant HDFN.
Anti-Cha is an antibody with high titer, low avidity (HTLA) characteristics. The
antigen is not an integral part of the RBC membrane but rather is formed in
the fluids and adsorbs onto the RBC. The antibody has weak reactivity and a
low binding ability. The antigens are not fully developed at birth and the
antibody is weak and not capable of causing HDFN. So you can rule out that
antibody right away. In addition, you would likely see weaker reactions at
AHG in the mom's serum tested with the antibody panel, and the infant DAT
would be negative.
Doa is an antigen that is expressed as a part of the RBC membrane, Anti-Doa
can cause HTR, but does not typically cause HDFN. The antigen is present on
about 65% of individuals from Northern European descent, so again, the
antibody would likely react in a routine antibody ID panel.
Coa is a high frequency antigen, so an anti-Coa in the eluate would have
reacted with all panel cells and the A1, B cells as well. IT would also show up
in the serum. Anti-Coa is capable of causing HDFN, but the pattern of
reactivity here does not correspond to the results for this situation.
Dia is a low prevalence antigen in Caucasians, African Americans, African
individuals and European individuals. The antigen is positive in
approximately 11% of Native Americans, about 2% in South Americans, 12%
in Japanese, 5% in Chinese and 1% in Hispanic populations . The antibody is
capable of causing HDFN. So the pattern displayed in this case is consistent
with the antigen and antibody. It is likely that the panel cells are lacking Dia
antigen since the majority of donors (of blood components and reagent RBCs
tend to be Caucasian).
In a case like this, you would want to focus on testing cells positive for low
prevalence antigens. You could also test the father's cells to determine if it is
, in fact an antibody causing hemolysis, but the strong positive DAT (3+)
already tells you that there is an antibody present. SO testing the father's
cells in a case where the DAT is so strong is not likely to give you additional
information.
-Which of the following statements is true regarding the donation of red
blood cells by automated methods?
A. The deferral period after the donation of a combination of a single unit of
red cells and a single unit of platelets by apheresis is 16 weeks.
B. The copper sulfate method of determining hematocrit cannot be used to
qualify a donor for double red cell donation.
C. Donor weight and donor hematocrit requirements for double red cell
donation are the same as those for whole blood donation.
D. Double red cell donation is associated with a higher frequency of reactions
compared to whole blood. - -Correct: The copper sulfate method of
determining hematocrit cannot be used to qualify a donor for double red cell
donation.
AABB requires a quantitative method for determining hemoglobin/HCT, with
a minimum Hematocrit of 40% from both genders of donors.
" The deferral period after the donation of a combination of a single unit of
red cells and a single unit of platelets by apheresis is 16 weeks." is a false
statement. If a single unit of RBCs is collected, then we treat it the same as a
routine WB donation, so the deferral period is 8 weeks.
" Donor weight and donor hematocrit requirements for double red cell
donation are the same as those for whole blood donation. is also a false
statement. WB donors have no height requirement-only a minimum weight
requirement of 110 pounds. RBC apheresis donors have minimum weight
and height requirements based on gender. Males minimum height is 5'1" and
minimum weight of 130 pounds. Females have a minimum height of 5'5" and
weight of 150 pounds
" Double red cell donation is associated with a higher frequency of reactions
compared to whole blood." There is no evidence to support this statement. In
fact, the opposite is true. Apheresis donors are typically selected from
donors who have had multiple donations, so are more prepared for the
effects of blood donation. Even in first time apheresis donors, the rates of
donor reactions are not higher than with WB donors."
-Which of the following autologous donors is eligible to donate?
A. A 75 year old male with prostate cancer whose hemoglobin is 10 g/dL. He
is otherwise healthy and is scheduled for a prostatectomy in 3 weeks.
B. A 35 year old male paraplegic with infected decubitus ulcers over the
sacrum, hemoglobin 13 g/dL, debridement and skin grafting in 14 days.
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