Rh and LW

Question 1

Rh + means

Answer 1

presence of D antigen

Question 2

Rh - means

Answer 2

absence of D antigen

Question 3

D antigen is present on only what?

Answer 3

RBCs

Question 4

clinical significance of Rh antigen

Answer 4

high immunogenicity

Question 5

other Rh antigens

Answer 5

50 others
most common: D, C, E, c, e

Question 6

3 theories of Rh gene inheritance

Answer 6

Wiener
Fisher-Race
Tippet

Question 7

Fisher-Race theory of Rh gene inheritance

Answer 7

3 closely linked loci inherited as a unit
D C E
1 gene 1 product per allele
letter designations

Question 8

dosage definition

Answer 8

amount of Ag present on a homozygous cell vs. amount of Ag present on a heterozygous cell

Question 9

genotype determination of dosage

Answer 9

can estimate genotype based on the rxn stregth of phenotyping results

Question 10

R2 cells

Answer 10

cDE
stronger expression of D
react more strongly with anti-D reagent

Question 11

Gene position effect of antigen strength: cis effect

Answer 11

labialization of ligands that are cis to other ligands

Question 12

E antigen produced by R2 gene (cDE) is _____ than E antigen produced by r gene (cdE)

Answer 12

weaker

Question 13

R1 cells

Answer 13

CDe gene

Question 14

weak D

Answer 14

Du
less antigenic sites

Question 15

c gene in trans position to D results in

Answer 15

D antigen weaker expression

Question 16

partial D, D mosiac, D variant

Answer 16

lack of a part of the D antigen

Question 17

blood donors (testing for D antigen)

Answer 17

tested for weak D and D

Question 18

blood recipients (testing for D antigen)

Answer 18

tested for D not weak D

Question 19

Ce (rhi) R1 gene (CDe)

Answer 19

Ce on same haplotype

Question 20

ce (f)

Answer 20

c and e on same haplotype

Question 21

G antigen

Answer 21

present on most D+ and all C+ cells
anti-G combo antibody created in response

Question 22

D negative person makes both anti-__ and anti-___

Answer 22

anti-D
anti-C

Question 23

Rh negative person can make anti-G antibody to the ___ antigen

Answer 23

G

Question 24

LW antigens

Answer 24

present on most human RBCs
D neg have weaker LW activity

Question 25

anti LW

Answer 25

reacts with D pos cells
weakly with D neg cells

Question 26

Rh null

Answer 26

very rare
no Rh antigens
absence of regulator genes
“amorph”
RBC membrane abnormalities

Question 27

Rh null blood type must transfuse with what blood type?

Answer 27

Rh null

Question 28

immunogenicity of Rh antibodies ranked least to most

Answer 28

least=> most
e< C< E< c< D

Question 29

antibodies that exhibit dosage

Answer 29

dependent on hetero/homozygosity
anti-E vs anti-e
anti-C vs anti-c

Question 30

R1 (CDe) patients can create what anti- “combo”

Answer 30

if we find anti-E always type for anti-c

Question 31

reagent albumin must always have an Rh control because of what?

Answer 31

spontaneous agglutination of the albumin reagent

Question 32

Rh discrepancies are mostly due to what?

Answer 32

positive DAT
sensitized patient cells + high protein reagents = positive Rh (spontaneous agglutination)

Question 33

what is the resolution for a positive Rh control?

Answer 33

wash cells w/ saline 3x and redo testing
perform a DAT
retest with a low protein reagent

Question 34

false positives in Rh testing

Answer 34

wrong reagent added
contaminating Ab
polyagglutinable RBCs
autoagglutinins/ ab. proteins
contaminated reagent

Question 35

false negatives in Rh testing

Answer 35

wrong reagent added
reagent not added
variant antigen
procedural
weak agglutination
contaminated reagent