Monday, 27 August 2007

Haematology

Kleihauer Test

It is to determine the distribution of fetal Hb in red cells and especially useful in determining the presence of fetal RBC in the maternal circulation.

Principle:
HbF will be able to resist acid elution to a greater extent than normal cells whereas HbA (adult) gets denatured in these conditions. Red cells containing HbF will be deeply stained whereas cells with HbA will give a ghost-like appearance.

Procedure:
1. Fix blood film with 80% ethanol for 5 mins

2. Rinse with distilled water and dry

3. Immerse in elution solution (haematoxylin & ferric chloride) for 20s.

4. Rinse thoroughly with distilled water

5. Counterstain with eosin for 2 mins

6. Rinse with water and dry

7. Examine under microscope

Results:
HbF level should be <0.01% for adult.
-Adult red cells appear as ghost-like pale pink.
-Fetal cells stain densely red.

QC:
A normal adult blood (negative) and cord blood (positive) should be stained together.

Clinical significance:
It is a sensitive procedure which identifies individual cells containing HbF even when few are present, and their detection in the maternal circulation has provided valuable information on the cause of hemolytic disease of the newborn.


Eunice
TG02
0503245C

6 comments:

J.A.M.M.Y.S said...

hiya,
i would like to ask a question ya. How come HbF will be able to resist acid elution to a greater extent than normal cells? eh can explain? Thanks ya.

Michelle
TG01

J.A.M.M.Y.S said...

hiya,
i would like to ask a question ya. How come HbF will be able to resist acid elution to a greater extent than normal cells? eh can explain? Thanks ya.

Michelle
TG01

VASTYJ said...
This comment has been removed by the author.
VASTYJ said...

hi eunice~~

hmm, is this the test performed after giving birth to check for D+ RBC from fetal right? then they will administer rhogam

Chaur Lee

Distinction in Disaster! said...

Hi

Can you explain why HbA will denature during acid elution?

Thanks.

Adrian TG01

MedBankers said...

qns: HbF will be able to resist acid elution to a greater extent than normal cells?

ans: HbF is relatively stable under low pH which may have something to do with the molecular structure and overall charge.

qns: is this the test performed after giving birth to check for D+ RBC from fetal right? then they will administer rhogam

ans: Yes..if the test shows that the maternal blood is "contaminated" with fetal blood, Rh immunoglobin (RhIg) or Rhogam™ will be administered.

eunice