Antibody identification

Question 1

What are the sources of alloantibodies?

Answer 1

• Naturally occurring Ab: i.e. ABO Ab
• Immune Ab: Foreign RBC Ag from transfusion, pregnancy, sharing needles
• Passively acquired Ab: e.g. prophylactic anti-D

Question 2

Which antibodies are commonly identified in WA?

Answer 2

1. Anti-E (16.8%)
2. Anti-M (15.0%)
3. Anti-D (13.6%)
4. Anti-K (10.3%)
5. Anti-Lea (9.8%)
6. Anti-C (8.4%)
7. Anti-Leb (5.1%)
8. Anti-Fya (4.2%)
9. Anti-c (3.7%)
10. Anti-S (1.9%)
11. Anti-Jka (1.4%)

Question 3

Discuss the process of antibody identification.

Answer 3

1. Rule out / cross out
2. Match the pattern
3. 2+2 rule: Ab react 2≤ RBC & not react w/ 2≤ RBC

Question 4

Explain how enzymes can be used for the identification of weak antibodies.*

Answer 4

• • enzymes can enhance detection of Ag

- can make a reaction stronger = stronger/higher grading

Question 5

Explain why antibodies against high and low frequency antigens are rarely encountered

Answer 5

• High incidence Ag = most ppl in pop have that Ag = they don’t make that Aby = rarely encounter that Aby
• Low incidence Ag = low # ppl in pop have it = less likely to be exposed to Ag = low Aby made = Aby uncommon

Question 6

Why we perform Ab Id?

Answer 6

• On Pos Aby screen
• prevent & manage HTR & HDNB
• Management of HDN
• Give Ag neg cells = prevent sensitize I.Sys

Question 7

Things to consider when looking at patient’s history
- Age
• Ethnicity
* Clinical history & transfusion history

Answer 7

• Newborns: Aby come from mum
• Elderly: immunodef. = lo [Aby] & Hi chance to have 1+ Aby
  • Ethnicity: most Asians Rh(D) pos
• Pregnancy: High chance make allo-Aby (from prev. preg
• Transfusion history: High chance make Allo-Aby

Question 8

multiple grades in a cell panel indicates =

Answer 8

• single Aby demonstrating dosage

- Multiple Aby present in same sample

Question 9

A single antibody will give the same reaction grade against multiple cells except those aby…

Answer 9

• Aby demonstrating dosage (multiple grades in same rxn grade)
• Aby reacting against Ag - has variable expression e.g. Anti-P1

Question 10

Characteristics of Anti-E Aby that are detectable on long cell pannel

Answer 10

Anti-E reacts w/ cell 4, 5, 7

Question 11

Characteristics of Anti-K Aby that are detectable on long cell pannel

Answer 11

Anti-K reacts w/ cell 2 & 8

Question 12

Characteristics of Anti-D Aby that are detectable on long cell pannel

Answer 12

Anti-D reacts w/ cells 1-5

Question 13

what does it mean (hint) if rxn grades in long cell panel

a) jump 1+ rxn grade (e.g. 2+ -> 3+)
b) 2 rxn grade (e.g. 2+ -> 4+)

Answer 13

a) Aby demonstrating dosage

b) multiple Aby present in sample/plasma

Question 14

E.g of High incidence Ag & what to expect at long cell panel

Answer 14

e. g. k, Coa, U, Lub, Kpb, Jsb
- reacts against most/all cells except auto
* if have autoAby, reacts to ALL cells including auto