Practical 2: RhD Grouping

Question 1

What does RhD positive mean

Answer 1

Red cell bear the D antigen

Question 2

What does RhD negative mean

Answer 2

Red cells don’t bear the D antigen

Question 3

What must also be ran when running an RhD test?

Answer 3

RhD control must be ran

Question 4

What are the two anti-D anti-sera called?

Answer 4

RUM-1
MS201

Question 5

What should the results of the RhD control be?

Answer 5

It should always be negative

Question 6

For how long should you incubate your tubes?

Answer 6

5 to 10 minutes

Question 7

How should you centrifuge your tubes

Answer 7

centrifuge at 2000rpm for 30seconds (P2)

Question 8

What is the other method other than tubes of grouping patients?

Answer 8

Gel/column agglutination technique

Question 9

What gel is used for ABO grouping

Answer 9

BioRad ABO and Rh D grouping gel cards

Question 10

When should you not use a gel?
(4)

Answer 10

If they show signs of drying

If they have bubbles

If the seals are damaged

If there are drops of gel or supernatant in the upper part of the microtubes or on the underside of the aluminium foil

Question 11

How much rbcs should you add to the ID card

Answer 11

10ul (in notes)

50ul (in practice)

Question 12

How much plasma and reagent cells should you add to the ID card

Answer 12

50ul of reagent cells

50ul plasma

Question 13

For how long should you centrifuge the cards?

Answer 13

10 minutes

Question 14

What is the reverse grouping cards called?

Answer 14

ID-DiaCell ABO

Question 15

What is a positive ID card result

Answer 15

Agglutination of cells which form a red line on the surface of the gel or agglutinates dispersed in the gel

Question 16

What is a negative ID card result

Answer 16

Compact button of cells on the bottom of the tube

Question 17

What does it mean if you have a button and a red line in your ID card?

Answer 17

Mixed field

Question 18

What causes a mixed field?

Answer 18

Bone marrow transplant

Blood transfusion

Question 19

What are the seven controls for the ABO + RhD test
(7)

Answer 19

Colour of anti-sera

Anti-AB

2 anti-Ds against different D epitopes

RhD control

Reverse group

Daily controls (to see if reagents and anti-sera are working)

Daily controls (double check cell type)

Question 20

What is the principle of gel technology
(4)

Answer 20

Sephadex gel matrix acts as a sieve

Large agglutinates remain on or near the top of the gel interface

Smaller agglutinates pass partway through gel depending on their size

Un-agglutinated cells pass to base of microtube to form a button

Question 21

What is different about how we use gels in the college versus the lab

Answer 21

Lab will use a foil piercing device and a dilution pipette

• don’t have to dilute rbcs by hand

Question 22

Give two brands of gels used in Ireland

Answer 22

BioRad

Ortho Biovue

Question 23

How does BioRad differ from Ortho Biovue

Answer 23

BioRad uses gel

Ortho Biovue uses glass beads

Question 24

What must you be careful to do when pipetting into the gels

Answer 24

Disperse liquid on side of reaction chamber -> not directly onto gel or into the air gap