How often do you do an antibody workup on the same patient?

[jojo808]

Not sure if it was posted before but I was wondering in the case of a patient who regularly comes in once a month and has an antibody (ours has a Anti-E, Jka) would you do a workup every single time the patient came in?

 

Would you just do select cells? (E,Jka neg cells to rule out any new allo antibodies)

If so, would you do this every month?

 

Or, would you not do any panels if the antibody screen strength stayed the same?

 

 

 

 

[Malcolm Needs ☆]

As a Reference Laboratory, we would do it every time....................but that's just us!!!!!!!!!!!!!!!!

[Teristella]

We do selected cells. We have quite a few recurring patients come through our outpatient infusion center and a number of them have developed antibodies.

[Dansket]

We repeat antibody identification only if an antigen-negative screen cell is positive or antigen-negative donor unit is incompatible.  We do not use reaction strength or time since last workup. See AABB Technical Manual 16ed.  At the end of the Antibody Identification chapter.

[Malcolm Needs ☆]

I should ad, perhaps, that in cases of DAT positive patients, who are regular "customers", we would not perform an eluate every time they arrive at our doorstep, even if they are regularly transfused.

[jojo808]

Thank you for the responses. And I will definitely review that Chapter in the technical manual (thanks Dansket).

[SMILLER]

Every time.

 

Scott

[goodchild]

The AABB standards specify "in patients with previously identified clinically significant antibodies, methods of testing shall be those that identify additional clinically significant antibodies."

 

You really should do selected cells with each encounter. You're required to if you're AABB accredited.

 

The only exception we have is if we do antibody identification with one sample, know with a high level of confidence that the individual hasn't been transfused in the last three months, and the patient has been continuously admitted; with subsequent samples the ABID may be cancelled.

[DebbieL]

We repeat a panel once a month if the patient meets certain criteria. We perform a screen (3 cell) and it must match what we expect it should. The cells that should be negative are negative. We crossmatch antigen negative units and they should be AHG negative. If the patient meets this criteria, we only do a panel once a month. The techs are always hoping the last panel was within the previous month so they don't have to do one.

If the screen shows a cell as positive that we weren't expecting to be positive, repeat the panel. If the antigen negative units are crossmatch positive, repeat the panel. If the patient has a warm autoimmune antibody, panels and eluates are done every three days.

My previous boss put this in place many years ago. I thought we were going to have reactions right and left when we started this but it works very well. It is a big time saver, frees up the techs and we save money. 

[David Saikin]

I would run selected cells to r/o any new sensitizations.

[MAGNUM]

We repeat it each and every time. With the number of healthcare facilities in our area, we feel that the patient could have been transfused elsewhere and could possibly "create" new antibodies. Just being safe.

[mollyredone]

We do as DebbieL does; if antibody screen is consistent with the previously identified antibodies and the gel crossmatches are compatible we only do a panel every 30 days.

[Dr. Pepper]

We repeat the panel every 21 days (an artibrary choice), otherwise, we do as everyone else - use selected cells to rule out what we can't with the negative ab screen cells and repanel if something new seems to have popped up.

[kate murphy]

We do selected cell panel at every new admission or out-patient encounter.

[goodchild]

The concept of going by the screen and only repeating antibody ID panels on a schedule seems so foreign to me that I'm kind of amazed by it.

 

To the hospitals that go by a policy of this nature

 

1. Do you have generalist techs?
2. How often do you see incompatible crossmatches and find additional antibodies?
3. If the patient has either multiple antibodies or a single antibody that leaves the entire screen positive, do you consider that an expected result and stop there?

 

Isnt there concern for underlying antibodies that could be missed at crossmatch due to strength/dosage or because of diminished reactivity with subsequent encounters?

[Malcolm Needs ☆]

4.  Or possibly another antibody that reacts with the expected screening cells, but is a different specificity, that is not detected in the IAT cross-match because, unlike the screening cells, which are in a preservative that is designed to "keep antigenicity", but not "oxygen carrying capacity", the unit's red cells are kept in a preservative that is designed to "keep oxygen carrying capacity", but not "antigenicity", and, in any case, may only have heterozygous expression of an antigen, whilst the screening cells have homozygous expression of an antigen.  Why take the risk with a patient's life, and your own future in the profession?

[goodchild]

Thank you for saying what I meant in a better way than I could have accomplished.

[SMILLER]

I get the idea of using selected cells (negative for known Abs) in order to rule-out any other (new) Abs, but I never saw the logic in assuming because a screening panels results look the same that one could assume on that alone, that no more Abs have developed.

 

Scott

[Sandy L]

Antibody screen plus antibody ID which consists of selected cells to rule out any additional new antibodies on every specimen.

[John C. Staley]

The AABB standards specify "in patients with previously identified clinically significant antibodies, methods of testing shall be those that identify additional clinically significant antibodies."  I'm curious, how is it that this could not be understood to mean " only if an antigen-negative screen cell is positive or antigen-negative donor unit is incompatible"?  That was my interpretation and I passed many an AABB inspection with that in my SOP manual.   Now, obviously, no one will fault you for doing more but I find this totally acceptable.

[Dansket]

 

The AABB standards specify "in patients with previously identified clinically significant antibodies, methods of testing shall be those that identify additional clinically significant antibodies."  I'm curious, how is it that this could not be understood to mean " only if an antigen-negative screen cell is positive or antigen-negative donor unit is incompatible"?  That was my interpretation and I passed many an AABB inspection with that in my SOP manual.   Now, obviously, no one will fault you for doing more but I find this totally acceptable.

 

John,

See page 495 (Frequency of Antibody Testing) of the 16th edition of the AABB Technical manual. If there is an antigen-negative screen cell that is not agglutinated and two (2) or more antigen-negative donor units that are anti-IgG crossmatch-compatible on a current blood sample, there is no evidence supporting the presence of additional antibody. I believe the standard as written supports this approach. I have been doing this for more than a decade without incident.

Do you run a selected cell panel for every sample with a positive antibody screen with a history of anti-D or anti-K1? I do not.

Dan

Edited July 7, 2014 by Dansket

[goodchild]

Do you run a selected cell panel for every sample with a positive antibody screen with a history of anti-D or anti-K1? I do not.

Dan

 

We do.

[goodchild]

The AABB standards specify "in patients with previously identified clinically significant antibodies, methods of testing shall be those that identify additional clinically significant antibodies."  I'm curious, how is it that this could not be understood to mean " only if an antigen-negative screen cell is positive or antigen-negative donor unit is incompatible"?  That was my interpretation and I passed many an AABB inspection with that in my SOP manual.   Now, obviously, no one will fault you for doing more but I find this totally acceptable.

 

I guess our interpretation is a conglomeration of the AABB standards and the tech manual.

 

According to the technical manual the common clinically significant antibodies that should be excluded with antibody identification testing are anti-D, -C, -E, -c, -e, -K, -Fya, -Fyb, -Jka, -Jkb, -S, and -s.

According to the standards, "patients with previously identified clinically significant antibodies, methods of testing shall be those that identify additional clinically significant antibodies" and "when clinically significant red cell antibodies are detected or the recipient has a history of such antibodies, Red Blood Cell components shall be prepared for transfusion that do not contain the corresponding antigen" (5.14.3)

 

Relying on the antibody screen and AHG compatible units may detect but would not be useful in identifying additional clinically significant antibodies and if you weren't performing methods to detect antibodies to the other common clinically significant antibodies then how could you say you were appropriately providing antigen-negative RBCs?

 

As a follow up to Dansket's comment about a patient with a positive antibody screen and a history of anti-D:

Looking at our current antibody screen antigram we could be missing an underlying anti-C, -E, -K, -Fya, -Jkb, -Lea, or -s. This could be missed at crossmatch for reasons that Malcolm already mentioned.

 

Perhaps we're also just very cautious due to our geographical location (we're in the city and there are dozens of other hospitals in the immediate area) and our antibody caseload (we seem to pick up quite a number of significant antibodies and bring several delayed serological/hemolytic reactions to the medical director for review each month).

[Dansket]

 

Relying on the antibody screen and AHG compatible units may detect but would not be useful in identifying additional clinically significant antibodies and if you weren't performing methods to detect antibodies to the other common clinically significant antibodies then how could you say you were appropriately providing antigen-negative RBCs?

 

My impression is that the words "identify" and "detect" are being used interchangeably. If I detect something then I will identify. If an antigen-negative screen cell is agglutinated or antigen-negative donor unit is anti-IgG crossmatch-incompatible, I do antibody identification.

Which edition of the AABB Standards is being quoted here?

[goodchild]

28th.