Transfusing IAT positive red blood cells

[AP44924]

Hello,

I am wondering about, a donor that has an antibody, and has donated whole blood that is seperated into plasma and red cells. Is it safe to tansfuse this unit of red cells to a patient who positive for corresponsding antigen without washing the unit or other modifications to the unit. Please help

[vilma_mt]

I don't think there's going to be a significant harm to patient. Not a whole lot different from giving a type O single donor platelet to a type A/B patient which is a common practice. Basically packed red cells have small amount of plasma left in the bag. As far as I know donor centers clearly label this units and most often offer them to big facilities with a lot of patients with antibodies. The hospitals then use these units on patients that match antibodies.

[Eagle Eye]

I think question is can we give Red cells to a patient who is positive for those antigen. The antigens to corresponding antibody present in Donor's plasma.

We do not accept any donor with postive antibody screen so our blood supplier doesn't send us those units.

[Fluffy agglutinates]

It will depend on several factors:

For neonates the donation must be antibody screen neg by IAT

For donations intended for adults in the UK the antibody screen is done by enzymes using a 2 cell pool covering D, C, E , c, e & K. The following rules are then applied:

Pos on neat screen - all products ok for adult use

Red cells in SAG-M can be used with a pos screen at a dilution of up to 1 in 50. All other products have a dilution limit set at 1 in 10 (i.e. if screen is pos the product is discarded or used as a reagent).

The reasoning behind this is; within a given donation there is a finite amount of antibody present. When transfused to an adult this will be diluted by their blood volume & not have any effect. There is also evidence to show that the only antibodies likely to affect an adult will be strong examples of Rh & K. So in the UK we do not do an IAT screen unless the donation is intended for paediatric use.

In a small volume person - neonate - the dilution factor does not exist & all clinically significant antibodies could potentially cause harm. Therefore an IAT screen is essential.

Does your blood service perform an IAT screen on all donations as standard?

[Malcolm Needs ☆]

It will depend on several factors:

For neonates the donation must be antibody screen neg by IAT

For donations intended for adults in the UK the antibody screen is done by enzymes using a 2 cell pool covering D, C, E , c, e & K. The following rules are then applied:

Pos on neat screen - all products ok for adult use

Red cells in SAG-M can be used with a pos screen at a dilution of up to 1 in 50. All other products have a dilution limit set at 1 in 10 (i.e. if screen is pos the product is discarded or used as a reagent).

The reasoning behind this is; within a given donation there is a finite amount of antibody present. When transfused to an adult this will be diluted by their blood volume & not have any effect. There is also evidence to show that the only antibodies likely to affect an adult will be strong examples of Rh & K. So in the UK we do not do an IAT screen unless the donation is intended for paediatric use.

In a small volume person - neonate - the dilution factor does not exist & all clinically significant antibodies could potentially cause harm. Therefore an IAT screen is essential.

Does your blood service perform an IAT screen on all donations as standard?

The other thing is, of course, in the UK, because of the theoretical/actual threat of passing on vCJD in blood, we no longer accept donors who have themselvews either received a blood transfusion or a transplant of certain tissues, and so there are far less donors these days that will have antibodies in their plasma (those stimulated by pregnancy excepted).

Certainly though, there is one case in the literature (now, a bit of an ancient paper, I must admit) of one unit of whole blood, containing a strong anti-K, being transfused to a K- recipient, followed by a unit of K+ blood being transfused, and this K+ blood reacting with the passive anti-K that had entered the recipient's circulation from the earlier unit.

:eek::eek:

[Fluffy agglutinates]

We did have a case once where a patient appeared to produce a cracking anti-K (titre at least 1/1024) after transfusion of K- units. The hospital lab was most annoyed to find out that it had come from the donor! Also made reporting the antibody status on the patient history very tricky...

Of course this anti-K only reacted in IAT so wasn't detected by the donor testing lab.

[Malcolm Needs ☆]

We did have a case once where a patient appeared to produce a cracking anti-K (titre at least 1/1024) after transfusion of K- units. The hospital lab was most annoyed to find out that it had come from the donor! Also made reporting the antibody status on the patient history very tricky...

Of course this anti-K only reacted in IAT so wasn't detected by the donor testing lab.

"titre" "1/1024" Oh Fluffy - that's a dilution, not a titre!

:(:redface::(

[Fluffy agglutinates]

My apologies oh master of transfusion terminology! Please spare the rod this time...

[Malcolm Needs ☆]

My apologies oh master of transfusion terminology! Please spare the rod this time...

Tee hee!!!!!!!!!!!!!

:D:D:D:D

[adiescast]

We routinely transfuse antibody positive red cell (AS3 or AS5) units to adults whose antigen status is unknown. We do look at them first for patients with that antibody, since they are a quick source for antigen negative blood. Obviously, you would never use these units for a neonate. We have not had problems with this policy. I see more positive DATs from out of type platelets than from antibody positive red cells.

[John C. Staley]

For most of us, we would never know the donor had a positive antibody screen so the question does not apply. When I supervised a full service hospital blood bank we drew our own donors. We were not concerned with donors who had antibodies when it came to transfusing their packed RBCs. Their plasma on the other hand was not used for transfusion.

:eek:

[tricore]

"titre" "1/1024" Oh Fluffy - that's a dilution, not a titre!

:(:redface::(

Malcom,

You are now the "John Judd" of BB Talk. He was always correcting our terminology on the aaBB forums. Are you ever allowed to cross the pond to the aaBB meetings?

Michele

[adiescast]

The plasma is lovely for teaching students, doing competency evaluations, and training new techs. We also use it to make our QC reagent.

[Marilyn Plett]

The other thing is, of course, in the UK, because of the theoretical/actual threat of passing on vCJD in blood, we no longer accept donors who have themselvews either received a blood transfusion or a transplant of certain tissues, and so there are far less donors these days that will have antibodies in their plasma (those stimulated by pregnancy excepted).

Certainly though, there is one case in the literature (now, a bit of an ancient paper, I must admit) of one unit of whole blood, containing a strong anti-K, being transfused to a K- recipient, followed by a unit of K+ blood being transfused, and this K+ blood reacting with the passive anti-K that had entered the recipient's circulation from the earlier unit.

:eek::eek:

Now that packed cells are the norm, I'm not convinced that paper is relevant to current transfusion practice. And it becomes even less relevant if RBCs are suspended in an additive solution. We did a brief study of antibody titers in ADSOL-RBCs and found the titers to be similar to anti-A and anti-B titers. In the US, Group O RBCS are frequently transfused to patients of other blood groups with little thought as to the impact of anti-A and/or anti-B.

[Malcolm Needs ☆]

Now that packed cells are the norm, I'm not convinced that paper is relevant to current transfusion practice. And it becomes even less relevant if RBCs are suspended in an additive solution. We did a brief study of antibody titers in ADSOL-RBCs and found the titers to be similar to anti-A and anti-B titers. In the US, Group O RBCS are frequently transfused to patients of other blood groups with little thought as to the impact of anti-A and/or anti-B.

Agreed Marilyn; that was why I put in the bit about the paper being somewhat ancient.

:D:D:D:D

[Malcolm Needs ☆]

Malcom,

You are now the "John Judd" of BB Talk. He was always correcting our terminology on the aaBB forums. Are you ever allowed to cross the pond to the aaBB meetings?

Michele

Actually, although I haven't been (yet - I would love to), the NHSBT does allow a few people to go every time, but you have to do something, rather than just go (like present a poster or something - not too difficult, but finding the time is another thing - and convincing my wife that I should go to the USA without her).

:fear::fear::fear:

[adiescast]

Actually, although I haven't been (yet - I would love to), the NHSBT does allow a few people to go every time, but you have to do something, rather than just go (like present a poster or something - not too difficult, but finding the time is another thing - and convincing my wife that I should go to the USA without her).

:fear::fear::fear:

We would love to have you come, but I have to agree with your wife. A trip across the ocean is too good to pass up. I would be very unhappy if my husband had an opportunity to come to the UK and didn't really work to find a way to take me with him. I took my husband to the meeting in New Orleans and the one in Los Angeles. (He wasn't available to go to Montreal, so that wasn't my fault!)

[AP44924]

My thoughts were along the same lines, but being a novice blood banker, I figured I am better off turning to the "pros" in blood banking. I did find papers about washing red cells before transfusing, but again a old paper. Thank You again. If I may also ask for links to some other papers?????

[tubeshaker]

The facility in which I worked previously would transfuse units from donors with antibodies randomly for all but anti-D (excepting peds), and these we would only transfuse to D-negative recipients.

In addition to the uses for the plasma proposed by Adiescast, I had an agreement with our community blood center to send me the antibody-positive units to use for antigen screening on the Galileo using the IgGXM assay. I built up quite a library before I left, and they really came in handy when you had to screen for multiple antigens (or even for 1 when the antisera was expensive). I could screen a couple hundred units for 3 or 4 antigens in 3 hours or so (using expired Capture-R Select plates). A lot cheaper than using up the commercial reagent (I'd only use it to confirm negative screening results) and we didn't have to rely on our reference lab all the time, which was about 2 1/2 hours away.

Cheers,

JD

[John C. Staley]

The facility in which I worked previously would transfuse units from donors with antibodies randomly for all but anti-D (excepting peds), and these we would only transfuse to D-negative recipients.

JD

I'm curious, was the only reason units with anti-D treated differently because you had a convient way to know if the patient was antigen positive or not?

:abduction

[tubeshaker]

I'm curious, was the only reason units with anti-D treated differently because you had a convient way to know if the patient was antigen positive or not?

:abduction

Hi John,

No, there was a perception that it could potentially cause harm to a D-positive recipient. Many of the policies in the institution were there not based on any rationale other than "that's the way it's always been." The practice was probably a holdover from the days when they were transfusing whole blood and no one ever thought to update the SOP. I look back nostalgically on pretending to read antibody screens from EDTA samples for hemolysis when it was time for internal competency evaluation. One of the downsides to low turnover, I suppose.

Cheers,

JD

[Malcolm Needs ☆]

I look back nostalgically on pretending to read antibody screens from EDTA samples for hemolysis when it was time for internal competency evaluation.

Love it!

It still amazes me that so many people use AHG containing anti-IgG and anti-C3d, when they are using EDTA plasma!

Doh!

:):)

[tubeshaker]

Love it!

It still amazes me that so many people use AHG containing anti-IgG and anti-C3d, when they are using EDTA plasma!

Doh!

:):)

[Malcolm Needs ☆]

Love it!

It still amazes me that so many people use AHG containing anti-IgG and anti-C3d, when they are using EDTA plasma!

Doh!

:):)

Hi Malcolm,

I may be off, but wouldn't a positive DAT due to anti-C3d in an EDTA sample make one more confident that complement had been activated in vivo? I've asked the same question of others and haven't gotten an answer, so I've formed my own set of assumptions - that because C3 binding to the complement receptor on the red cell is a covalent interaction, once it occurred removing Ca++ from the mix (when the cells hit EDTA) wouldn't matter, C3b would remain bound, but that no further activation would occur without Ca++ to stabilize the recognition unit. I guess I just assumed that's the reason we still use polyspecific AHG when testing samples collected in EDTA.

I'm really glad I found this forum, all those burning questions I've had in the back of my mind are getting answered left and right (more often than not by you, it seems). Hopefully you can clear this one up for me as well.

Thanks,

JD