Antibody ID Flashcards
Do you phenotype auto-Ab positive or negative?
Only auto-Ab negative can be phenotyped
Haplotype
Antigens inherited together on same chromosome
Clinically significant Ab
- React at body temp and can cause HDN and/or HTR (some type of immune response)
- Can destroy transfused Ag-pos RBCs
Allo-antibody
- Preventable
- Patient missing Ag
- Treat by transfusing compatible cells
- Same species but diff person from you
Auto-antibody
- Unrelated to transfusion
- Patient has the antigen
- Treat by transfusing only as necessary
Auto-control
- self vs self
- Pt RBCs 3% solution against Pt plasma
Phenotype (referring to protocol)
- Self vs antibody
- antibody is known reagent
Antibody ID
- Self vs cell
- Pt plasma vs known screen cells
Low-incidence Ag
Less than 10% of population
Give examples of low-incidence Ag
- Cw
- V
- Kpa
- Jsa
- Lua
High-incidence Ag
Greater than 90% of the population
Give examples of high-incidence Ag
- Kell sellano (k)
- Kpb
- Jsb
- Lub
- Leb
HTLA stands for
High Titer Low Avidity Antibodies
Describe HTLA
- Weakly reactive but really big titer
- May block other Ab from being detected
- Do not cause HDN/HTR, so clinically insignificant
How do you diagnose HTLA?
- Antibody Titer: You serially dilute the antibody and test to see if it’s still there at super dilute levels
- HTLA will be present no matter how dilute
Give two examples of HTLA
- Chido/Rogers
- JMH
How do you remove Chido/Rogers if it’s causing HTLA disturbance?
Neutralize with plasma
How do you remove JMH if it’s causing HTLA disturbance?
Destroy with enzyme
What do HTLA titer results look like?
The bottom row shows HTLA
List all steps for finding compatible blood from start to finish
- ABO blood type fwd + rvs
- Ab Screen
- Ab panel (big screen) + auto-control
- Select cells
- Phenotype
- Find compatible blood
- AHG crossmatch
Antibody screen procedure start to finish GO!
- 2 drops pt plasma + 1 drop screen cells I/II/or III and do IS reaction grade
- Add 2 drops of LISS
- 15 min inc at 37°C and do reaction grade
- Wash 4x
- Add 2 drops anti-IgG
- AHG reaction grade
- Add 1 drop check cells to negative reactions only
Rule of 3 is for
Rule in only
T/F
Auto-control results may indicate if a patient was transfused or not
True
How many points for 1 homozygous rule out?
2
How many points for 1 heterozygous rule out?
1
Which antigen systems are exceptions to the rule of 3 and why?
- Kidd and Duffy because high dosage
- Homozygous rule outs only
T/F
Always phenotype patient blood
False
Always phenotype donor blood
When do you phenotype patient blood?
- New antibody found
- Patient not previously typed for antigen
When do you NOT phenotype patient blood?
- Auto-control has mixed-fixed field
- Recent transfusion (past 2-4 wk)
- Already phenotyped for antigen
When do you NOT phenotype donor blood?
- Ab is non-specific and/or antisera for Ag doesn’t exist
- Ab clinically insignificant
- Ab is auto-antibody
If auto-control is positive in the IS phase, where will you see issues?
ABO typing
If auto-control is positive in the AHG phase, where will you see issues?
Phenotype testing
An auto-control gives a mixed-field result. Is this valid?
a. Yes, the result shows the patient has an auto-Ab
b. Yes, the patient has probably been recently transfused
c. No, the panel cells cannot give mixed field results, something is wrong with the test system
d. No, the control has failed, the test must be repeated until it gives valid results
b. Yes, patient has probably been recently transfused
What is phenotype testing?
After you have ID’d the Ab, you want to prove yourself right by testing patient RBCs against known antisera (for Ab you ID’d) and expect no agglutination because patient should not have the antigen it has made an antibody against
