Crossmatch & Blood Typing (ATE2639L)

Question 1

Saline Agglutination Test

Answer 1

Must distinguish RBC agglutination from rouleaux
* agglutination + spherocytes = IMHA
* test confirms agglutination or not
* agglutination occurs due to excess antibodies on cell surfaces

Question 2

Saline Agglutination
Test Set-up

Answer 2

• Drop of saline on clean slide
• Add 1 drop of EDTA blood to same slide and mix
• If positive, RBCs will remain clumped even in thin areas

Question 3

Buffy Coat

Answer 3

• Layer mainly consists of WBCs and platelets
• Reticulocytes may be observed here with intense regeneration - ting area red

Question 4

Buffy Coat Smear
Purpose

Answer 4

• Concentrates cells
• WBC count <1,000 /uL
• Mast cell tumor staging
• Neoplasia screening
• Blood parasite detection

Question 5

Buffy Coat Smear
Preparation

Answer 5

• Spin 2 PCV tubes
• Score tubes just below buffy coat (into packed RBCs)
• Break tube at scored area - get as little RBCs as possible
• Blow buffy coat onto slide
• Do squash or push smear
• Dry and stain

Question 6

Canine Blood Types

Answer 6

8 Blood Groups
* DEA 1-8
* DEA 1.1 and 1.2 are major antigens

Question 7

Canine Blood Types
DEA 1.1 and 1.2

Answer 7

• Can be either negative for both or positive for one or the other (but not both)
• Negatives do not have natural antibodies - acute hemolytic reaction if mixed with Positives
• First transfusion ok to do without crossmatch, but antibodies will become known after

Question 8

Feline Blood Types

Answer 8

1 Blood Group
* A
* B
* AB

Question 9

Feline Blood Types
How Common

Answer 9

A
* most common of domestics

B
* most common with exotic breeds

AB
* Uncommon
* Universal recipient

Question 10

Feline Blood Types
Antibodies

Answer 10

• Type B has anti-A antibodies
• Type A has anti-B antibodies
• Type AB has no antibodies

Question 11

Feline Blood Types
Crossmatching

Answer 11

Always crossmatch before transfusion, even first round
* anti-antibodies in both types A and B blood can result in illness / death
* type AB can get type AB or Type A blood (type B has too high of antibodies)
* type A getting type B blood = mild reaction
* type B getting type A blood = severe reaction +/- death

Question 12

Crossmatching Procedure

Answer 12

Perform if been longer than 4-7 days since last crossmatch
* collect blood from both D and R into EDTA tubes
* centrifuge for 5 minutes to separate plasma from packed RBCs
* transfer plasma from each into new tubes
* “wash” packed RBCs with saline 3 times
* make RBC suspension (1 drop RBC : 20 drops saline)
* make Major, Minor, and Control tubes
* incubate for 15-30 minutes
* centrifuge briefly
* examine tubes for hemolysis and macro agglutination
* make slide and examine for micro agglutination

Question 13

Crossmatch Procedure
“Major” Combo

Answer 13

• 2 parts Recipient plasma
• 1 part Donor cells (RBC suspension)

Question 14

Crossmatch Procedure
“Minor” Combo

Answer 14

• 2 parts Donor plasma
• 1 part Recipient cells (RBC suspension)

Question 15

Crossmatch Procedure
“Control” Combo

Answer 15

Performed with Recipient blood to check for auto-agglutination (may indicate auto-immune disease)
* 2 parts Recipient plasma
* 1 part Recipient cells (RBC suspension)