We have had a situation where we would do the antibody screen using PEG, all reactions were negative, but the check cells would never work. We tried up to six washes. We tried not using the cell washer and washing by hand, and that didn't work. We finally did the screen with albumin, because we don't have LISS in our lab. The check cells worked with the albumin.

Is anyone aware of any situations where the use of PEG might inactivate the AHG in later phases of testing? Or any other reason for this situation to occur?

I tried looking through the forums, and honestly got tired of trying to find a post concerning this, so I apologize if the answer is already on here.

Thanks in advance!

It is odd that your check cells were negative . . . I was going to comment that sometimes cell washers are not efficient enough since PeG causes agglomeration but it seems that you have that covered. I wash my PeG tubes by hand - 4 washes always suffices. I use 10x75 tubes. I do not have an answer for your dilemma - sorry.

We used PeG for several years before switching to Gel and never had this happen. Occasionally there would be a check cell failure, but repeating it always worked, so it surely had to be the washing. I will be curious to see if anyone has an answer for you, as we do still use it for certain situations.

Same here as BankerGirl. Basic troubleshooting says look to see if any reagent or solution was changed just prior to the difficulties experienced. Another suggestion is to redraw the patient sample as something as quirky as the tube may have caused the difficulty. Let us know how your investigation turns out.

Laughing out loud on this one because we just had this happen today! Drove ourselves a little crazy repeating it multiple times, washing different ways, etc. This particular patient was giving us difficulty in gel due to rouleaux, so we were trying to do the PeG screen, and check cells were negative. After washing more than 6 times, the check cells started coming up weakly positive. At least for THIS patient, our explanation seems to be: the increased protein in his plasma causing all the rouleaux problems requires a ridiculous amount of washing to remove??? Does this seem reasonable to anyone else? Because at this point I'm guessing...

Seems reasonable to me. With the oncology population we serve excessive protein has caused many "strange results". Wouldn't put this past protein concentration either.

Did you try changing your check cells, or trying a different lot? I've noticed that sometimes 2 drops of check cells are needed.

The check cells were fine with every other patient, including QC. We ruled out every possible scenario (while scratching our heads) trying to figure out why just THIS patient would not check cell. Weird...

The check cells were fine with every other patient, including QC. We ruled out every possible scenario (while scratching our heads) trying to figure out why just THIS patient would not check cell. Weird...

One of the hospitals that uses us as a Reference Laboratory reported that they could tell whether or not one of their myeloma patients was in remission or relapse by the number of washes the IAT required before the IAT could be shown to be valid by the use of IgG-coated red cells.

We have seen that with patient having protien problems. We use gel for the most part now, but PeG was our enhancement for years. We even saw flocullence in some samples as soon as we added PeG. On those samples, we used LISS because the extra washes didn't always work.

I am not familiar with PeG.

Does the PeG rouleaux the cells, so reinforce the rouleaux caused by the abnormal protein? This makes the wash not so efficient?

Edited September 18, 201014 yr by shily
spelling correction

John -

If you are observing this check cell problem with just one (or "a few") patients, my experience supports tbostock's explanation submitted on 9/16/10. If you are seeing the problem with most or all of your patients, I agree with David Saikin's 9/16/10 reply.

Donna

We've also seen the flocculation problem with some patients - I call it PeG clouds. The protein explanation seems reasonable to me. The patients we have problems with seem to be oncology patients or elderly patients with multiple problems. I've found washing x4 to be helpful, but I've never seen one that needed more washes than that. Something to be aware of - thanks for the thought!

"PeG clouds"...I love it!:floating:

John, I didn't realize that this was you.

If this is just one patient and you were able to get good results using albumin I would not spend a lot of time worrying about this Unicorn. Probably something unique with this patients protiens as others have mentioned. I do like the term "PeG cluods". Sounds like you did all the resonable things to work it out.

Folks, John worked for me as a Transfusion Service Night Tech and one of the better ones we had. I understand he recently moved into a new position on the day shift and I wish him well. I hope to see many more posts from him in the future.

PEG (polyethylene glycol, Yanxia) does sort of "trap" protein. That is why the cell washer has to completely resuspend cells between washes (some brands don't) if used for PEG. Otherwise it is best to wash by hand. Since some myeloma patients have immunoglobulin levels many multiple times normal, they could require way more washing than normal. Have you checked the protein or immunoglobulin levels on this patient?

Thank you very much, Mabel.

We have been noticing weaker check cell reactions, sometimes variabley, for the past ~2 months. This kinda coincided w/when we changed from a 20L cube of saline to a 10L cube of saline.

Use to get strong 3+'s, now get from weak 3+(gently shake) to srtong 1+. We use tubes w/PEG.

Checked the cell washer dispense volumes = ok

Checked the saline pH (on a lark) = 5.6, 5.9. aahhhhh. (Subsequent pH checks were ok-6.5, 6.7)

Called Immucor - they have had customer complaints of "weaker check cell reactions" for about 2 months. (Our sister hospital has also noticed some weaker rxn's.) Per Immucor, they are working on it. Unsure of the cause.

Anyone else see this?

Just love when the reagent manufacturer is getting complaints, and "are working on it", but don't feel it necessary to give all of their customers a "heads up". Each of us will struggle on our own before we find out it is a "known issue". OK, that's my rant for the day.

That's why I love this site.

We can quickly find out if others are seeing the same problems.

Yes- i so agree.

So now we are hand washing, to see if that makes a difference. If so, we'll rpt w/hand washing any CC value less than 2+s (on every patient?????) have the cell washers maintenanced, (what are the chances that 2 different cell washers both have a decanting problem at the same time???), and whatever else I can come up with...gggrrr

Just a question. Has something changed in your shipping practices? Overnight delivery versus 3 day? Also, do shipments have cooling packs or at least some sort of insulation?I have seen that happen when shipments get a little warmer than usual. We had that happen with shipments of complement coated cells.

As far as the original question about PEG and check cells, I have seen numerous problems with check cells not working when dealing with patients with elevated protein. PEG precipitated the protein (sometimes turned white as milk) and then you could not wash it away.

Checked the cell washer dispense volumes = ok

Checked the saline pH (on a lark) = 5.6, 5.9. aahhhhh. (Subsequent pH checks were ok-6.5, 6.7)

Called Immucor - they have had customer complaints of "weaker check cell reactions" for about 2 months. (Our sister hospital has also noticed some weaker rxn's.) Per Immucor, they are working on it. Unsure of the cause.

Anyone else see this?

I'm sorry but I'm am confused with this. Was the saline with the pH of 5.6, 5.9 taken directly from the cube? Did you do anything to alter the pH to get the 6.5, 6.7? Just what reagent is Immucor working on? When the pH was at 6.5, 6.7 were the check cells working as expected?

John,

How old is the PEG in use; when was it opened? Do you use PEG regularly?

We have had this occur on a couple of our patients. We noted that when the PEG was added it was extremely Milky in appearance. The protein binds to the tube and is not easily removed. We found that it was necessary to wash once with saline then fill the tubes with saline and transfer the suspension to a new tube and then wash the cells before adding the AHG.

"I'm sorry but I'm am confused with this. Was the saline with the pH of 5.6, 5.9 taken directly from the cube? Did you do anything to alter the pH to get the 6.5, 6.7? Just what reagent is Immucor working on? When the pH was at 6.5, 6.7 were the check cells working as expected?"

The original pH was from the cell wash dispense. That was repeated and slighlty different values were obtained. The saline was also pH'ed directly from the cube. Not felling too good about the varied answeres. The reagent in question was Immucors Check Cells - we've noticed weaker readings and have tried to troubleshoot.

As far as I know, theres been no difference in shipping. The cell washer manufactureer suggested a slight change in the "decanting' rate/speed.

For now - we are useing the freshest cells (usually have 3 lot #'s on hand), and if the CC is 2+weak or less, we are hand washing. I'm wondering if the CC's aren't as stable as they used to be...