Two questions: irradiation & positive eluate

[Generic]

Good morning,

I have two separate questions I have been wondering about and thought I'd ask them here.

1) Is it safe/allowable to irradiate a unit of LRBCs more than once? I am almost certain that I read somewhere that you should discard a unit rather than irradiating twice. This makes sense to me as I'd imagine the amount of damage to doubly irradiated cells would be quite high, resulting in an increased amount of potassium and an expiration date that could not be determined. Would these factors matter if the unit was going to be immediately transfused after irradiation?

2) This one may be a no brainer, but I wanted to make sure I wasn't missing something...Is it possible to have an auto-anti-E if you have been previously typed as E negative? I ask because I'm not sure if it is possible to have a partial E or something of that sort. A coworker performed an ABID on a patient with a previous anti-E and showed a 4+ reaction with E positive cells; the patient had a positive autocontrol and positive DAT. The eluate showed a 1+ reaction on the E positive cells. I believe she failed to wash the red cells adequately before eluting, and I cannot find where she recorded the results of her final wash. The only other possibility that I can think of is that the patient may have recieved a transfusion of E positive RBCs at another hospital. Thoughts?

Thanks for your input.

[Ajac]

It is not okay to irradiate a second time. Why should you anyway? FDA doesn't like that sort of thing if you are in the US.

Q2: Yes, it is possible for that type of thing to occur. Look up Matuhasi-Ogata phenomenon. I have seen this type of non-specific binding before when testing eluates, although it is rare. I would certainly investigate the chance that the patient had been elsewhere and received E+ unit. Has this patient's antibody always been that strong? If antibody was no longer detectable, bingo. Just curious, did you E type them again? If transfused, they might be mixed field positive.

[LaraT23]

As far as question 1, I agree with Ajac. Definitely not okay, the FDA is quite clear about.

Question 2, I had happen here actually. This is one phenomenon I am still puzzling out, as I do not quite buy what my reference lab is telling me.

Scenario: Patient has historical anti-K, has been transfused about 3 weeks ago with K neg units. Now, shows with E and K and is typed as E negative and K negative. Her DAT was 1+, we sent out the elution ( although I am strongly now considering doing them myself) and the report shows that the eluate is reactive with all cells, but more strongly with E and K positive cells. Strange, as the patient is herself phenotyped as K and E negative and has been receiving K neg units. We may have given her the E pos units last month, as her E was not showing so that one does make a tiny bit of sense. So, what say you all about the K issue? This patient has been receiving K negative units since 07/05, when her K antibody first reared its ugly head.

Edited October 20, 2010 by LaraT23
added more information

[Malcolm Needs ☆]

As for question 1, why would you want to irradiated again? The whole point of irradiation is that it disrupts the DNA in any viable T lymphocytes, so that they cannot engraft after transfusion. Once the DNA is disrupted, it is VERY unlikely to be able to repair itself. It remains disrupted, so irradiating it a second time would seem like tortology.

As for question 2, yes.

Auto-antibodies, as I have posted before, can be extremely good mimics of other specificities, and auto-antibodies that mimic common antibody specificities within the Rh Blood Group System are extremely common.

Sorry Lara, but we have also been following a patient from a hospital on the south-east coast of England now for several years who is K-, has not received K+ blood or blood components for years and years, and yet we can elute an (apparent) anti-K from the red cells every time we test samples from this patient.

I know not why, unless it is the Matuhasi-Ogata phenomenon.

:confuse::confuse:

[Mabel Adams]

The easy part is--give the patient units neg for E (& K for the other patient) and try not to worry about it.

I once worked with a patient whom we transfused monthly. He was E neg & D pos and had a fairly weak panagglutinin but always reacted more strongly with E pos cells and sometimes D pos cells (I find this more in gel than we used to find in tube). He seemed to go longer between transfusions if we gave him E neg Rh neg units. Sometimes I could talk the Dr. into putting him onto steroids for awhile and his auto would get weaker. I never knew whether the anti-E was auto or allo but we never wanted to give him E+ blood so it didn't really matter. When he moved to Calif to be near his daughter, we sent a card with our phone # with him to give to the Blood Bank at his new hospital and when they called we filled them in--on mostly what we didn't know about his antibodies, but it is always nice to be ignorant together.

[David Saikin]

I would think your auto-anti-E is an example of the Matahasi-Ogata phenomenon. If they are E negative, it cannot be an auto-anti-E. It may be an autoab with a predilection for the E epitpoe.

[DPruden]

In answer to #1: We had that same question about re-irraditating here when a rad-sure was not applied to the unit before the irradiation process. The techs wanted to re-irradiate to save the platelet, but unfortunately the answer is to discard the product. It can no longer be labeled as non-irradiated or irradiated and the FDA is very firm on not allowing mislabeled products.

to #2: I would think the most probable explanation is transfusion at another facility. We have had a couple of patients who hop back and forth between hospitals and lead us down a merry path trying to figure out their situations.

[vilma_mt]

Good morning,

I have two separate questions I have been wondering about and thought I'd ask them here.

1) Is it safe/allowable to irradiate a unit of LRBCs more than once? I am almost certain that I read somewhere that you should discard a unit rather than irradiating twice. This makes sense to me as I'd imagine the amount of damage to doubly irradiated cells would be quite high, resulting in an increased amount of potassium and an expiration date that could not be determined. Would these factors matter if the unit was going to be immediately transfused after irradiation?

2) This one may be a no brainer, but I wanted to make sure I wasn't missing something...Is it possible to have an auto-anti-E if you have been previously typed as E negative? I ask because I'm not sure if it is possible to have a partial E or something of that sort. A coworker performed an ABID on a patient with a previous anti-E and showed a 4+ reaction with E positive cells; the patient had a positive autocontrol and positive DAT. The eluate showed a 1+ reaction on the E positive cells. I believe she failed to wash the red cells adequately before eluting, and I cannot find where she recorded the results of her final wash. The only other possibility that I can think of is that the patient may have recieved a transfusion of E positive RBCs at another hospital. Thoughts?

Thanks for your input.

I believe FDA allows up to 2 irradiations, not exceeding 5000 cGY. But must be documented as such indicating total dose. I have read this in one of the "ask the FDA" forums awhile back. I tried looking for the FDA Guidance/Regulation with no luck.

[jcdayaz]

I believe FDA allows up to 2 irradiations, not exceeding 5000 cGY. But must be documented as such indicating total dose. I have read this in one of the "ask the FDA" forums awhile back. I tried looking for the FDA Guidance/Regulation with no luck.

Why would someone want to irradiate the same unit twice? The logic behind that escapes me.

[JoyDenver]

I agree that you do not want to irradiate twice, but why discard the unit? Please consider transfusing it to a patient who does not require irradiated products.

[nmartin]

In the FDA Guidance for Industry.. Gamma Irradiation of Blood and Blood Components - Feb 2000

They state "at no time should the total irradiation dose exceed 5000 cGy to any portion of the container".

So I think this might answer your question..

[JOANBALONE]

For those that use Elukit - the IFU addresses this nonspecific uptake phenomenon. The package inserts suggests washing 4 times with saline instead of working wash solution. Has anyone tried this and did it work?

[JOANBALONE]

Sometimes the irradiator may malfunction during a cycle (or someone forgets to put a RadSure on a unit). We complete an error report and will use the unit for someone who does not require irradiation.

[Generic]

Thanks for all your replies.

With regards to my question on irradiating a unit twice, I didn't mean to imply that it was desirable or somehow more effective. I was thinking along the lines of a unit that didn't have a RadSure sticker placed on it, like dpruden and joanbalone mentioned, or if the label fell off. I was able to find an old memo (http://www.fda.gov/downloads/BiologicsBloodVaccines/GuidanceComplianceRegulatoryInformation/OtherRecommendationsforManufacturers/MemorandumtoBloodEstablishments/UCM062815.pdf) on the FDA website that said that if a product is irradiated more than once, each instance should be recorded and the total amount calculated (it did not give a maximum amount of total cGy). From that and the guideline nmartin referred to (http://www.fda.gov/OHRMS/DOCKETS/98fr/981218g2.pdf) it sounds like you can irradiate twice, as long as you don't exceed 5000cGy, like vilma_mt said. I have to admit this surprised me...

As far as my second question, I checked the patient's history and she was admitted in early August and has only received platelets and E negative blood since she has been here. None of her other workups showed this result. Just out of curiosity, my coworker did an eluate on a sample drawn a week before the one showing the "auto"-anti-E, and I just did one on a sample drawn yesterday, and both eluates were negative. So I'm assuming either she didn't wash well enough or this is the non-specific uptake referred to in the Elukit instruction sheet. I'd hoped the elution I performed would turn up positive so I could try the saline washes, but no luck...

Edited October 29, 2010 by Generic
typo

[Malcolm Needs ☆]

Thanks for the follow-up Generic.

[Liz]

Yes, Thanks for the follow up.