Blood Bank

boc4 immunology
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A Good Friend Who is specialist in Immunohematology (Blood Bank) answered the following Question.
Thanks to Marlene , This explanations are very helful.
(1) Rh-  mother has increase titer of anti-D. After delivery, the DAT is strongly (+) but the baby is            Rh-

   a) inadequate washing
   b) added monoclonal anti-D sera instead of anti globulin (or vise versa)
   c) or maternal antibodies blocking the antigenic site
C: maternal antibody blocking the antigenic site giving you a false negative D typing at immediate spin and IAT.  The baby’s RBCs are coated with maternal IgG that the anti-D in the commerical reagent can’t bind to the baby’s red cells so you get a false typing.

(2)3 units of FFP requested for A – patient

Available: A- =1unit
                A = 6units
                O- = 5 or something 
a) transfuse  A units
b) transfuse O negative
C) don’t remember more options
The Rh typing doesn’t matter when transfusing FFP units because there aren’t any RBCs in FFP so you can transfuse A- or A+ or AB+ or AB-

(3)What is the reason for this discrepancy or What would you do to resolve this discrepancy?

  Patient cells                                        Patient serum
anti-A   anti-B                                     A cells    B cells
    3+           3+                                            1+               0
Answer:  This is a reverse group discrepancy, most likely to a subgroup of A.
A2 subgroup is most commonly seen in patients that are AB, about 25% of them make anti-A1.  So this is most likely due to A2B patient making anti-A1


(4) In forward, reverse reaction… reaction in forward, but no reaction in reverse, what will do you?
A.  Incubate at room temp for 15-20 minutes.  The reverse reaction is usually due some immunodepressed event and the reactions will reveal.
The reverse typing antibodies, i.e. anti-A and anti-B and anti-A,B contain IgM as well as IgG antibodies.  IgM antibodies are enhanced after room temperature and 4C incubation so incubation at room temp or 4C will enhance and usually reveal these antibodies.


(5)You suspect someone might have Jka, K and c antigens on their red cells. You figure out that they don’t have Jka. You also test their serum and see the following:

                                                reagent K cells                         reagent c cells
patient serum:                               0                                                     4+
What can you conclude?
a. confirm patient as having K and c antigens on their red cells
b. rule out c and confirm K on their red cells
c. rule out c and K
d. rule out c but cannot confirm the presence or absence of K

Answer: D is the correct answer.The fact that the patient hasn’t made anti-K doesn’t tell you if they are positive or negative.  They could be negative for K antigen and never make anti-K.  The only thing that you know if that their blood is reacting with c antigen and most likely they made anti-c because they are c antigen negative.

(6)What is RHOGAM, when are you going to give it and what will it do to the patient?

In a nut shell it’s an injection containing passively acquired anti-D.  It is given to D negative mothers during 28 weeks of pregnancy and up to 72 hours after delivery to prevent the formation of actively acquired anti-D from a baby that’s D positive.

In an emergency, what blood type of blood would you give if the red cells are needed or plasma is required and the blood type is unknown?

 In emergency situation when there is no time to perform proper tests give O- RBCs and AB FFP.  These are the universal blood type for RBCs and plasma products.


 (8)Would you phenotype a patient who had been transfused within the last 3 months?

No because you may get mixed field typing which is the patient’s blood and transfused blood and may get false results.
(9) What is the isoagglutinations in type O?
Anti-A, anti-B and anti-A,B(10).Mother B Rh(-), Father AB Rh (+). Child 1 A Rh(-) Child 2 B Rh (+). Which is correct

a.Parental is rule out b.Parental cannot rule out (answer) c.Child 1 can rule out  d.  Child 2 can rule out

your comment:  Based on this information you can’t not rule out the father.  Do you know how to do a punnet square?  If you do a square, you can see how this the mother can be a BB or BO and the father is a AB can have babies which is A, B, AB and O when the mother is BO but when the mother is BB the babies can only be B or AB.

(11)Anti- F will not react with:

a.       cDE CDE
b.      Cde CdE
c.       Cde Cde
d.      eDe CDe
Answer and Comment: anti-f reacts with RBCs that are c+e on the same haplotype.  So will not react with RBCs that are cDE or CDE or CDe or CdE or Cde or cdE but only with cDe or cde.  Does this make sense?


(12)The same antibody was found in 3 different patients. The results of testing are listed below. Which antibody is most likely to be present?

       IS         37           AHG
Patient 1    0           2+              0
Patient 2    2+         0                0
Patient 3     0          0               2+
a.  Anti – Jka
b. Anti- K
c. Anti- M

d. Anti- Leb

Answer and comment:  You want to chose a antibody that is known to commonly react at all phases and that is common enough where it’s most likely to be found in 3 different patients.  The likely answer is anti-M

(13)Which of the following is detected primarily in the antiglobulin phase of the crossmatch:

a.       Anti- Fya ( answer)
b.      Anti- M
c.       Anti- B
d.      Anti- P1

Anti-M, B, P1- are typically IgM and may agglutinate saline suspended cells at room temperature.

Comment: Anti-Fya contains mainly IgG and these are more likely to react in the antiglobulin phase of testing.

(14) The most common cold agglutinin? Answer:   Anti-I should be the correct answer

a.       I
b.      P1
c.       M       


(15)Multiple antibodies on the panel, what do you do next?  

You run a select cell panel to rule in and rule out antibodies 

 (16)Adminsitration of Rhogam to pregnant mother , how will it affect the child?
It is not known to affect the child 


Blood bank Notes from My Own

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