Cold Agglutinin Test

Question 1

Ii system

Answer 1

I: antigen found on adult RBCs. Anti-I agglutinins due to M. pneumoniae.

i: antigen found on newborn/cord RBCs. Anti-i agglutinins due to infectious mono.

Question 2

cold agglutinins

Answer 2

Autoantibodies that attach to RBC Ii antigens below 37° C and cause agglutination. Reversible. Mostly IgM.

Question 3

Raynaud’s phenomenon

Answer 3

pallor or cyanosis on hands or feet. sx of cold agglutination

Question 4

Differentiate a cold agglutinin titer due to M. pneumonia from one due to infectious mono.

Answer 4

M. pneumoniae: adult RBC reaction
Infectious mono: cord RBC reaction

Question 5

Explain how to select serum samples for cold agglutination.

Answer 5

Blood is drawn from red top tube and allowed to clot at room temp or warmer. Serum is separated and stored at 2-8° C for up to 7 days. Need minimum
1 mL serum.

Question 6

Explain why you need to use adult and cord type O RBCs for cold agglutination.

Answer 6

To distinguish between anti-I and anti-i, and help determine the original cause

Question 7

Explain quality control requirements for cold agglutination.

Answer 7

Cell controls should show no agglutination. Positive and negative control serums should also be run.

Question 8

cold agglutinins cause …. anemia

Answer 8

autoimmune hemolytic anemia

Question 9

besides infectious disease, ….. can cause cold agglutination

Answer 9

drugs

Question 10

cold agglutinins are sometimes seen in these 2 lymphoproliferative disorders

Answer 10

CLL
non-Hodgkin lymphoma

Question 11

cold agglutination typical age range

Answer 11

50s to 60s

Question 12

2 types of cold agglutinin disease
type of IgM

Answer 12

acute/transient – associated with infectious disease; heterogeneous IgM

chronic (CCAD) - idiopathic or related to lymphoproliferative disorders; homogeneous IgM

Question 13

cold agglutinin titers up to …. are considered normal

Answer 13

1:16