gel mystery

[Mabel Adams]

I just got a call at home from a tech at work describing a prenatal sample that is showing what looks like hemolysis in all 3 screen cells. Red in the reaction chamber, some red down into the gel and a slightly smaller than normal red cell button. The problem is, we use EDTA so hemolysis shouldn't be a possible endpoint. I haven't seen it so I suppose it could be something besides hemolysis, but it still sounds weird.

Other patients run at the same time do not show this reaction so it isn't that the cells are hemolysed already or hemolysing during testing non-specifically.

He has run the test twice so it probably isn't a contamination fluke. He will go ahead with a panel if for no other reason than to run some different cells and of course to see if there is any pattern.

She has historic results as an O neg with a negative screen.

I will be interested in whether the reverse type shows hemolysis (this will be by tube) and will recommend we test by LISS tube method before turning it out. Has anyone seen anything like this? Any ideas what it might be? Could it be any drugs she is on? Some flukey reaction with the diluent?

BTW, this lot of Ortho pre-diluted screening cells is showing us some non-specific reactions (mostly extremely weak) in cell 2. I think the lot is VSS104. Ortho said they had one other report of non-specific reactions so if you are seeing this too you might let them know.

[donellda]

It will be interesting to find out what it is. I haven't used gel for a few years but we had one OB patient that had an Anti-E and the pattern in gel was very odd. It looked like a single line of cells done the edge of the gel column with a small button at the bottom. I thought it was just a contaminant also but we did a panel and sure enough it was anti-E. Gel opens up some new findings. Our health system will be starting gel sometime this summer. I'm looking forward to using it once again:cool:

[Bob M]

Hi Everyone,

It looks like Mabel is using the newly reformulated Gel reagent cells (the lot number prefix looks like the new ones that we have). I have not seen hemolysis with the gel. We use EDTA primarily, like Mabel does.

We had another situation with one of the prior lots on a patient, and when we called OCD Tech Service, they recommended that we wash the cells and resuspend in Saline to the 0.8%, if we suspected a drug interference. Then, since there is no LISS in test system anymore, incubate for 30 minutes in the block (similar to a prewarm technic).

Like donnellda, we also have seen patients that show a "bi-phasic" response with a 4+ band at the top and a small button of cells at the bottom (it looks like the mixed field results in the manual, but since there is only screening cells, there aren't 2 populations). In the current Interpretation Guide from OCD, there is a page devoted to these Positive results. See page 23. We too have primarily seen this phenomenon on Anti-E. It can be disconcerting, since the mixed field can indicate rouleaux or cold antibodies also.

[rcurrie]

That "single line of cells down the edge of the gel column" was a problem with the gel and generated a technical recall a couple of years ago, so I don't think D's problem was due to the patient.

Mabel, just for grins, check the incubator out. It could have a hot spot in it that is hemolyzing the cells.

BC

[Mabel Adams]

I have seen an anti-E that looked like a cold antibody in gel and we get a fair number of anti-M's that show that bi-phasic look as well.

It is a good thought about the incubator having a hot spot. It is possible the tech put his repeat screen in the exact same well. He ran other screens at the same time initially and they were fine so it would depend on the card locations he used.

I will know more tomorrow, but the weekend tech said the cards don't look like hemolysis anymore, but there is now top-line. I suspect I got all excited over one of those cases where the red cells get hung up in the reaction chamber (static electricity, the book says) and then settle later onto the top of the column so they look like topline. I suspect there is something about this sample that made it prone to this since other samples at the same time were fine.

[Mabel Adams]

I guess it didn't really look like hemolysis after all. It was more like heavy haze in the gel columns. The patient ended up in ER by Monday so we had another sample on her that behaved the same way. It was neg with tube testing. Because we have had a lot of unexplained reactions with screen cell 2 this month I also tried this sample against the Gamma screen cells that I converted from 3% to 0.8% to run in gel and they were totally negative (no haze). Hmmm.

[Brad D. Ross]

We are a 4 hospital system in San Diego, Ca. Three of our four facilities have observed the same sort of reactions in screening cell 2, lot VSS 104, that you have described. We noticed that the reactions are repeatable using the SAME vial of screening cells. But if we open a fresh set of vials of the same lot, the reaction goes away. All panels performed with gel have been completely negative. We have observed this "reaction" in approximately 12 patients over the past week. We have also observed this same reaction in screening cell 3 once. We have reported this to Ortho. They are tracking it, so it would be helpful to Ortho if anyone else observing similar reactions reports it to them as well.