I apologize for posting because this subject has been covered many times.  Before posting I read some of the related threads, and I think I am on the right track, but I just want to make sure.

 

I have a specific situation, and 2 specific questions:

 

The situation:

 

Patient, GI bleeder, is O, Rh negative.  Patient received 2 units O, Rh negative pRBCs on 4/2/15 at another facility. 

 

On 4/10/15 the patient shows up at our small hospital, where we only perform tube ABO/Rh and manual gel antibody screens.  Antibody screen is weakly positive.

 

We send the specimen to our reference lab where a weak anti-Jk^a is identified.  However, the patient stabilizes at 9.0 hgb  and does not receive any blood products.  Patient is discharged 4/12/15.

 

On 4/18/15 I receive a call from the patient’s physician.  The patient has been bleeding.  His hemoglobin is 6.5.  The physician would like to order 2 units O, Rh negative units that are negative for Jk^a and transfuse the patient.

 

I tell the physician that because the patient was transfused so recently (4/2/15) and because the antibody workup was done on blood drawn 4/10/15, that, on 4/18/15, I would need to draw another sample and send the specimen to the reference lab for a repeat antibody workup.  The patient may have developed another antibody.  This is the policy at our facility.

 

We ended up sending the patient to a larger facility capable of a higher level of medical care.

 

My first question:

Was I correct about needing to test for additional antibodies?  A knowledgeable friend suggested it would have been okay to transfuse Jk^a negative units that were compatible at IgG....but but but... how could I be sure that another weak antibody wasn't lurking?   I think Malcolm has covered this subject in a related thread--the donor cells may be single-dose,  etc etc. 

 

I am looking at AABB Standards 5.14.3.2 and 5.14.3.3--A specimen from a patient that has been transfused in the last 3 months is only good for 3 days and patients with previously identified antibodies must be tested with a method to identify additional clinically significant antibodies.  A 3-cell antibody screen is not really a good method to identify additional antibodies

 

My second question:

In AABB Standard 5.14.3.2, how did the creators of this standard decide on three months?

 

I appreciate any comments and advice.  And thanks for your patience at revisiting this subject again!!!!

 

Catherine

Was your 3 cell screen on 4/18 now negative?   If so, I would do as your friend suggested.  

Let's answer question # 2 first. In any given unit of donated blood, the red cells are of all ages, new and older. So, since the life span of the RBC in the circulation is approximately 90 days, "recently transfused" means that there is a possibility of donor red cells still in circulation in the patient - therefore, foreign antigens are present that could elicit an antibody response up to 90 days (approx.).

Question #1 - I think you were correct in requesting another antibody work up. Especially with the severe drop in Hgb. If a patient has been recently transfused - with in 3 months, the specimen is only good to work with for 4 days - the day it's drawn plus 3.

Assuming you don't do antibody work ups at your hospital, I believe this patient needed an additional work up at the reference lab.

The 3 month rule is because the body can form an antibody to a foreign antigen at any time that foreign (donated) red cells are actively in the patient's circulation.

I hope that helps, and I'm sure my reference lab colleagues will have more to say

Liz

R1R2,

 

No, our antibody screen on 4/18 showed the Jk^a reaction was definitely stronger.  

 

Also, I did not mention this before, in order not to distract from my main question, there was an antibody present to the 0.8% screening cell preservative. 

 

When we performed the gel antibody screen with our usual 0.8% cells, all cells were positive at 2+.  The auto and DAT were negative, and when I XM'd all of our (8) units of O negative units, those XM's were compatible at gel IgG.  So I suspected an antibody to the preservative in the 0.8% cells.  As a backup, we have 3% antibody screening cells for tube, and I made 0.8% cells from these cells.  The antibody screen with the 3% cells made into 0.8% cells was negative. 

 

On 4/18 I ran a antibody screen with the 0.8% cells and the 3% cells made into 0.8% cells.  The 0.8% cells showed the Jk^a antibody and the antibody to the preservative.  The 3% cells made into the 0.8% and tested with gel IgG showed just the Jk^a.

I think Liz0316 has answered your questions perfectly, and there is NO way that I would not have asked for a fresh sample of blood to test.

HI, I am concerned about the antibody to the preservatives- can anyone recommend a good source of general information on this?  I have to wonder how many "nonspecific antibodies" we see on the Echo or in tube that are actually antibodies to a preservative. I have the thread about the 'solid phase antibodies" but have zero knowledge of manual tube testing possible preservative issues. All resources welcomed, thanks!

I agree with Liz and Malcolm.  You needed another specimen! 

Definitely another specimen.

Thanks Liz for the explanation of the 3 month period.  It makes sense and it will help me explain to physicians why we need to be concerned about more antibodies forming.

R1R2,

 

No, our antibody screen on 4/18 showed the Jk^a reaction was definitely stronger.  

 

Also, I did not mention this before, in order not to distract from my main question, there was an antibody present to the 0.8% screening cell preservative. 

 

When we performed the gel antibody screen with our usual 0.8% cells, all cells were positive at 2+.  The auto and DAT were negative, and when I XM'd all of our (8) units of O negative units, those XM's were compatible at gel IgG.  So I suspected an antibody to the preservative in the 0.8% cells.  As a backup, we have 3% antibody screening cells for tube, and I made 0.8% cells from these cells.  The antibody screen with the 3% cells made into 0.8% cells was negative. 

 

On 4/18 I ran a antibody screen with the 0.8% cells and the 3% cells made into 0.8% cells.  The 0.8% cells showed the Jk^a antibody and the antibody to the preservative.  The 3% cells made into the 0.8% and tested with gel IgG showed just the Jk^a.

Thanks for the additional info.   Additional testing was warranted.    

Also, the 0.8% Ortho red cells have a preservative in them that may effect patients with allergies to sulfa drugs. I'm at home now, and don't have the package insert in front of me, but the preservatives are different from the 3% cells and the 0.8% "gel ready" cells. Check to see if your patient has a sulfa allergy, that may explain the reaction differences you are seeing.

Liz

Antibody to the preservative with an underlying anti-Jk(a), I love it!

 

I add unique workups like that to the antibody ID powerpoint that I share with our students/new technologists.

goodchild, how about a DAT positive (4+) I had once, with an underlying anti-Vel, which I only knew about when I looked up the patient's past history?  Turned my own blood cold when I realised!!!!!!!!  Thank God we had seen the patient in the past, otherwise I suspect that we would not have seen the patient in the future!!!!!!!!