Unit 2: Rh Blood Group System

What are the 5 major antigens of the Rh system?

1. D

2. C

3. c

4. E

5. e

What nomenclature system theorizes that an individual inherits 3 Rh genes linked together as a haplotype group?

Fisher-Race (most commonly used)

What is the probable genotype (using Fisher-Race) for someone with a phenotype of: C+, D+, E-, c+, e+

White: CDe/cde

Black: CDe/cDe

What nomenclature system theorizes that Rh antigens are inherited as one gene and the system contains 8 alleles?

Wiener

What is used to represent the presence of the D antigen when using the Wiener nomenclature system?

R

What is used to represent the lack of the D antigen when using the Wiener nomenclature system?

r

What is used to represent the presence of the C antigen when using the Wiener nomenclature system?

1

What is used to represent the presence of the E antigen when using the Wiener nomenclature system?

2

What is used to represent the presence of both the C and E antigens when using the Wiener nomenclature system?

z (if D+)

y (if D-)

What is used to represent the presence of D antigen the lack of both the C and E antigens when using the Wiener nomenclature system?

R⁰

What is used to represent the lack of D antigen and both the C and E antigens when using the Wiener nomenclature system?

r

What nomenclature system numbers the Rh antigens and does not propose a genetic theory?

Rosenfield

What Rh antigen is the only antigen tested during routine pre-transfusion testing?

D antigen

What role does the D antigen play in blood typing?

D antigen present = +

D antigen not present = -

Majority of people are Rh (D antigen) (+/-).

+

True or False: A person may not inherit the RhD antigen, but they MUST inherit some combinations of C, E, c, and e antigens.

true

What term do we use when an individual lacks all Rh antigens on their RBCs (extremely rare)?

Rh null

What are 3 ways someone can be weak D?

1. trans-position effect: C antigen is opposite chromosome of D antigen, weakening its expression

2. genetically transmitted

3. categories of D: part of the D antigen is missing, weakening its expression

Why would we test to see if someone is weak D?

to ensure they are labeled as Rh+

When is the G antigen present?

when D and/or C antigens are present

When is f antigen present?

when c and e antigen are present (ce)

What antibody reacts with D antigens, mimicking anti-D?

anti-LW

True or False: Like the ABO system, our bodies naturally form antibodies to Rh antigens that our blood cells do not express.

false

Rh antibodies are (IgM/IgG) in nature.

IgG (antibodies only develop via sensitization ie. blood transfusions or pregnancies)

True or False: Rh+ patients can receive both Rh+ and Rh- blood, but Rh- negative patients should only receive Rh- blood unless in emergency situations.

true

What are 2 reasons why Rh antibodies are clinically significant?

1. hemolytic transfusion reactions (HTRs)

2. hemolytic disease of the newborn (HDN)

True or False: It is possible for a weak D individual to produce anti-D.

true (people missing parts of D antigen can create anti-D when exposed to D antigen that have the part they are missing)

What Rh antibody may be seen as an autoantibody in some individuals?

anti-e

What is the percent cell suspension used for Rh typing?

2-5%

When an why do we use a control when Rh typing?

AB+ individuals

we use a negative control to ensure spontaneous aggregation due to DAT hasn’t occurred (false +)

What is the major cause of false negatives in Rh typing?

technician error

The weak D antigen:

• Is considered Rh positive only if it reacts at saline immediate spin phase of testing

• Reacts with all anti-D reagents

• Reacts best at the antiglobulin phase of testing

• Is a phenomenon associated with an amorphic gene

Reacts best at the antiglobulin phase of testing

All of the following may be used as a Rh control with monoclonal reagents except:

• High protein manufacturer's control

• Monoclonal manufacturer's control

• 6% bovine albumin

• Patient's serum/plasma

High protein manufacturer's control

___ antigens has a frequency in the population of 85%.

D

___ antigens has a frequency in the population of 70%.

C

___ antigens has a frequency in the population of 80%.

c

___ antigens has a frequency in the population of 30%.

E

___ antigens has a frequency in the population of 98%.

e

What are the 4 most common phenotypes in order?

1. R1

2. r

3. R2

4. R

Name the most common Rh genotype for Rh negative individuals.

• cde/cde

• Cde/cde

• cdE/cde

• CdE/cde

cde/cde

What procedure is used to determine if a person is weak D positive?

• An immediate-spin direct testing procedure.

• A direct antiglobulin procedure.

• An indirect antiglobulin procedure

• An antibody screening procedure.

An indirect antiglobulin procedure

Interpret the following Rh reactions:

Anti-D = 3+ Rh Control = 1+

• Rh positive

• Rh negative

• Rh invalid

• Rouleaux

Rh invalid

True or False: If a patient has an anti-D in their plasma, it will be discovered in the Rh typing.

false (Rh typing is used to detect D antigen)

A person's Rh type is interpreted from:

• the cell typing only.

• the serum typing only.

• both cell typing and serum typing.

the cell typing only.