4.4 Testing for Antibodies Flashcards
A patient has the Lewis phenotype Le(a-b-). An antibody panel reveals the presence of anti-Lea. Another patient with the phenotype Le(a-b+) has a positive antibody screen; however, a panel reveals no conclusive antibody. Should anti-Lea be considered a possibility for the patient with the Le(a-b+) phenotype?
A. Anti-Lea should be considered as a possible antibody
B. Anti-Lea may be a possible antibody, but further studies are needed
C. Anti-Lea is not a likely antibody because even Leb individuals secrete some Lea
D. Anti-Lea may be found in saliva but not detectable in serum
Anti-Lea is not a likely antibody because even Leb individuals secrete some Lea
A medical laboratory scientist (MLS) is having great difficulty resolving an antibody mixture. One of the antibodies is anti-Lea. This antibody is not clinically significant in this situation, but it needs to be removed to reveal the possible presence of an underlying antibody of clinical significance. What can be done?
A. Perform an enzyme panel
B. Neutralize the serum with saliva
C. Neutralize the serum with hydatid cyst fluid
D. Use dithiothreitol (DTT) to treat the panel cells
Neutralize the serum with saliva
What type of blood should be given to an individual who has anti-Leb that reacts 1+ at the IAT phase?
A. Blood that is negative for Leb antigen
B. Blood that is negative for both Lea and Leb antigens
C. Blood that is positive for Leb antigen
D. Lewis antibodies are not clinically significant, so any type of blood may be given
Blood that is negative for Leb antigen
Which of the following statements is true concerning the MN genotype?
A. Antigens are destroyed using bleach-treated cells
B. Dosage effect may be seen for both M and N antigens
C. Both M and N antigens are impossible to detect because of cross-interference
D. MN is a rare phenotype seldom found in routine antigen typing
Dosage effect may be seen for both M and N antigens
Anti-M is sometimes found with reactivity detected at the immediate spin (IS) phase that persists in strength to the IAT phase. What is the main testing problem with a strong anti-M?
A. Anti-M may not allow detection of a clinically significant antibody
B. Compatible blood may not be found for the patient with a strongly reacting anti-M
C. Anti-M cannot be removed from serum
D. Anti-M may react with the patient’s own cells, causing a positive autocontrol
Anti-M may not allow detection of a clinically significant antibody
A patient is suspected of having paroxysmal cold hemoglobinuria (PCH). Which pattern of reactivity is characteristic of the Donath-Landsteiner antibody, which causes this condition?
A. The antibody attaches to RBCs at 4°C and causes hemolysis at 37°C
B. The antibody attaches to RBCs at 37°C and causes agglutination at the IAT phase
C. The antibody attaches to RBCs at 22°C and causes hemolysis at 37°C
D. The antibody attaches to RBCs and causes agglutination at the IAT phase
The antibody attaches to RBCs at 4°C and causes hemolysis at 37°C
How can interfering anti-P1 antibody be removed from a mixture of antibodies?
A. Neutralization with saliva
B. Agglutination with human milk
C. Combination with urine
D. Neutralization with hydatid cyst fluid
Neutralization with hydatid cyst fluid
Which antibody is frequently seen in patients with warm autoimmune hemolytic anemia (WAIHA)?
A. Anti-Jka
B. Anti-e
C. Anti-K
D. Anti-Fyb
Anti-e
A patient’s antibody shows strong reactions in all test phases. All screen and panel cells are positive. Serum is then tested with a cord blood cell, and the reaction is negative. What antibody is suspected?
A. Anti-I
B. Anti-i
C. Anti-H
D. Anti-p
Anti-I
Which group of antibodies is commonly found as cold agglutinins?
A. Anti-K, anti-k, anti-Jsb
B. Anti-D, anti-e, anti-C
C. Anti-M, anti-N
D. Anti-Fya, anti-Fyb
Anti-M, anti-N
Which of the following antibodies characteristically gives a refractile mixed-field appearance?
A. Anti-K
B. Anti-Dia
C. Anti-Sda
D. Anti-s
Anti-Sda
What does the 3+3 rule ascertain?
A. An antibody is ruled in
B. An antibody is ruled out
C. 95% confidence that the correct antibody has been identified
D. 95% confidence that the correct antibody has not been identified
95% confidence that the correct antibody has been identified
The k (Cellano) antigen is a high-frequency antigen and is found on most RBCs. How often would one expect to find the corresponding antibody?
A. Often, because it is a high-frequency antibody
B. Rarely, because most individuals have the antigen and therefore would not develop the antibody
C. Depends on the population, because certain racial and ethnic groups show a higher frequency of anti-k
D. Impossible to determine without consulting regional blood group antigen charts
Rarely, because most individuals have the antigen and therefore would not develop the antibody
Which procedure would help to distinguish between anti-e and anti-Fya in an antibody mixture?
A. Lowering the pH of test serum
B. Running an enzyme panel
C. Using a thiol reagent
D. Running an LISS panel
Running an enzyme panel
Which characteristics are true of all three of the following antibodies: anti-Fya, anti-Jka, and anti-K?
A. Detected at the IAT phase; may cause hemolytic disease of the fetus and newborn (HDFN) and hemolytic transfusion reactions
B. Not detected with enzyme-treated cells
C. Requires the IAT technique for detection; usually not associated with HDFN
D. Enhanced reactivity with enzyme-treated cells; may cause severe hemolytic transfusion reactions
Detected at the IAT phase; may cause hemolytic disease of the fetus and newborn (HDFN) and hemolytic transfusion reactions
