A D-negative pregnant woman's plasma reacts with D+C- cells and with D-C+ cells. Why does it matter whether this is anti-G or anti-D plus anti-C?

With anti-G alone she still needs Rh immune globulin

Anti-G causes more severe HDFN than anti-D

Anti-G means the fetus must be D-negative

Anti-G cannot cross the placenta

Monoclonal anti-D reagents for patient testing in the US are chosen not to react with partial D category DVI. Why?

So DVI patients type D-negative and receive D-negative blood

Because DVI cells carry no D antigen at all

Because anti-D from DVI people causes no HDFN

So that DVI donors are labeled D-negative

Antigens: Rh

11 ASCP MLS practice questions on Antigens: Rh, part of Blood Banking. The first 11 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Hard
A D-positive man types C+ c+ E+ e+. Using the common white haplotypes, his most probable genotype is:
1. ADCe/DcE (R1R2)
2. BDCe/dcE (R1r'')
3. CDce/dCE (R0ry)
4. DDcE/dCe (R2r')
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Answer: A · DCe/DcE (R1R2)
DCe (R1) and DcE (R2) are the two most common D-positive haplotypes in white populations. Together they give D, C, c, E and e, matching his typing. The other combinations give the same antigens but are built from much rarer haplotypes. The most probable genotype is the one made from the most frequent haplotypes.
- B: r'' (dcE) is rare compared with R2.
- C: ry (dCE) is extremely rare.
- D: r' (dCe) is rare compared with R1.
Question 2 · Hard
A D-negative pregnant woman's plasma reacts with D+C- cells and with D-C+ cells. Why does it matter whether this is anti-G or anti-D plus anti-C?
1. AAnti-G causes more severe HDFN than anti-D
2. BAnti-G means the fetus must be D-negative
3. CWith anti-G alone she still needs Rh immune globulin
4. DAnti-G cannot cross the placenta
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Answer: C · With anti-G alone she still needs Rh immune globulin
G antigen is present on almost all cells that carry D or C, so anti-G looks like anti-D plus anti-C. If she has true immune anti-D, Rh immune globulin no longer helps; if she has only anti-G, she has not made anti-D and still needs it. Adsorption and elution with D-C+ and D+C- cells separate the two. A reference laboratory usually does this testing.
- A: Anti-G is not more dangerous than anti-D; the issue is Rh immune globulin eligibility.
- B: Anti-G says nothing about the fetal D type.
- D: Anti-G is IgG and can cross the placenta.
Question 3 · Hard
Monoclonal anti-D reagents for patient testing in the US are chosen not to react with partial D category DVI. Why?
1. ABecause DVI cells carry no D antigen at all
2. BBecause anti-D from DVI people causes no HDFN
3. CSo that DVI donors are labeled D-negative
4. DSo DVI patients type D-negative and receive D-negative blood
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Answer: D · So DVI patients type D-negative and receive D-negative blood
DVI is the partial D most often associated with anti-D formation in white populations. If a patient's reagent misses DVI, the patient types D-negative and receives D-negative blood and Rh immune globulin, which protects them. Donor testing uses reagents that do detect DVI, so DVI units are labeled D-positive. The two rules together protect both patients and recipients.
- A: DVI cells carry D but lack several epitopes.
- B: Anti-D in DVI women can cause HDFN.
- C: Donor reagents detect DVI so the units are labeled D-positive.
Question 4 · Medium
A D-positive patient types C+ c- E- e+. Using the common white haplotypes, the most likely Rh genotype is:
1. ADCe/dce (R1r)
2. BDcE/dce (R2r)
3. CDce/dce (R0r)
4. DDCe/DCe (R1R1)
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Answer: D · DCe/DCe (R1R1)
The cells lack c and E, so both haplotypes must carry C and e. With D present, the most frequent combination is DCe/DCe (R1R1). DCe/dCe is possible but much rarer. Every other option would put c on the cells.
- A: R1r would carry c from the dce haplotype.
- B: R2r would carry c and E.
- C: R0r would carry c and lack C.
Question 5 · Easy
In the Wiener nomenclature, the Rh haplotype R1 corresponds to the Fisher-Race haplotype:
1. ADce
2. BDcE
3. CDCe
4. DdCe
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Answer: C · DCe
R1 is DCe, the most common Rh haplotype in white populations. R2 is DcE, R0 is Dce and r' is dCe. A capital R in Wiener terms means D is present; a lower-case r means D is absent. These names are used when predicting likely genotypes.
- A: Dce is R0, common in people of African ancestry.
- B: DcE is R2.
- D: dCe is r', which lacks D.
Question 6 · Medium
Weak D (formerly Du) is best described as:
1. AComplete absence of the RHD gene
2. BD antigen found only on reticulocytes
3. CAbsence of some D epitopes
4. DFewer D antigen sites per red cell
Answer and explanation in LearnFree account
Question 7 · Medium
A person with the common Rh-negative genotype dce/dce (rr) lacks which antigens?
1. AD, C and E
2. Bc and e
3. CD and E only
4. DD only
Answer and explanation in LearnFree account
Question 8 · Medium
Why are donor units tested so that weak D is detected, while many patients are not?
1. AWeak D donor cells can immunize a D-negative patient
2. BWeak D patients always form anti-D
3. CWeak D antigen is lost during storage
4. DFDA requires weak D testing of all patients
Answer and explanation in LearnFree account
Question 9 · Hard
A patient's red cells lack all Rh antigens, and the blood film shows stomatocytes with mild hemolysis. What is this, and what blood will the patient need if alloimmunized?
1. A-D- (deletion); D-positive units
2. BWeak D; D-positive units
3. CRhnull; Rhnull units from rare donors or relatives
4. DD-negative (rr); any D-negative units
Answer and explanation in LearnFree account
Question 10 · Hard
A woman who types D-positive with routine reagents has anti-D in her plasma after delivery. Her DAT is negative and she never received Rh immune globulin. The most likely explanation is:
1. AA weak D type 1 phenotype
2. BAnti-G mimicking anti-D
3. CA partial D phenotype
4. DA warm autoantibody with anti-D specificity
Answer and explanation in LearnFree account
Question 11 · Hard
A 45-year-old woman, last transfused after a car accident 6 years ago, has a positive antibody screen before hip surgery. The panel identifies anti-c; the autocontrol is negative at all phases. Her red cells type: anti-D 3+, anti-C 3+, anti-c 0, anti-E 2+, anti-e 3+, with valid controls, and her DAT is negative. She has no history of pregnancy. Using common haplotype frequencies in people of European ancestry, her most probable Rh genotype is:
1. ADCe/DCe (R1R1)
2. BDCe/dCE (R1ry)
3. CDCe/DcE (R1R2)
4. DDCe/DCE (R1Rz)
Answer and explanation in LearnFree account

Antigens: Rh

A D-positive man types C+ c+ E+ e+. Using the common white haplotypes, his most probable genotype is:

A D-negative pregnant woman's plasma reacts with D+C- cells and with D-C+ cells. Why does it matter whether this is anti-G or anti-D plus anti-C?

Monoclonal anti-D reagents for patient testing in the US are chosen not to react with partial D category DVI. Why?

A D-positive patient types C+ c- E- e+. Using the common white haplotypes, the most likely Rh genotype is:

In the Wiener nomenclature, the Rh haplotype R1 corresponds to the Fisher-Race haplotype:

Weak D (formerly Du) is best described as:

A person with the common Rh-negative genotype dce/dce (rr) lacks which antigens?

Why are donor units tested so that weak D is detected, while many patients are not?

A patient's red cells lack all Rh antigens, and the blood film shows stomatocytes with mild hemolysis. What is this, and what blood will the patient need if alloimmunized?

A woman who types D-positive with routine reagents has anti-D in her plasma after delivery. Her DAT is negative and she never received Rh immune globulin. The most likely explanation is: