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?
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?
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?
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?
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?
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?
Neutralization with hydatid cyst fluid
Which antibody is frequently seen in patients with warm autoimmune hemolytic anemia (WAIHA)?
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?
Anti-I
Which group of antibodies is commonly found as cold agglutinins?
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?
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?
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?
Detected at the IAT phase; may cause hemolytic disease of the fetus and newborn (HDFN) and hemolytic transfusion reactions
Refer to Panel 1. Which antibody is most likely implicated?
Anti-Jkb
Refer to Panel 2. Which antibody specificity is most likely present?
Anti-C and anti-K
On Panel 2, which of the following antibodies could not be ruled out?
Anti-C
On Panel 2, which cells are homozygous for C?
1, 2, 9
A 77-year-old female is admitted to a community hospital after a cardiac arrest. History includes an abdominal aortic aneurysm 2 years ago for which she received 6 units of packed RBCs. Her blood type is A positive, and the antibody screen is positive at the
AHG phase in screening cells II and III. A panel is performed by using LISS. In Panel 3, which antibodies are likely implicated?
E and c
What observation is apparent with one of the antibodies present on Panel 3
One antibody is only reacting with homozygous cells
