We've had our Echo for coming up on two years. In March of this year, we started seeing a new phenomenon. When we get Rh negative OB patients, very frequently they come up with an Anti-D pattern of at least 2 to 4+. The problem is when we do these manually (tube), they come up negative. If we send them to our reference lab, ALMOST always they come up negative for Anti-D. In ALL cases, these patients have gotten Rhogam.

I've tried to find a good way to handle this; we used to do the screen manually and report as negative, but because of those few Antibody ID's that were coming back positive, I felt we were not giving the docs the entire picture. So what we do now is to run the screen on the Echo, if it is positive, we run it manually. If it's negative, we report both workups WITH a comment saying when the patient got Rhogam and that manual testing methods showed no reactivity. It also asks the doctors to notify the lab if they want an ID done. Sometimes they do and sometimes they don't order one; I felt addressing it this way gives the docs all the information they need to make an informed decision about ordering an antibody ID, putting the ball in their court. Since we send these out, it's a significant extra cost for the patient.

I have some techs who hate doing it this way (they liked the other way that didn't involve as much work and thought), and some who think it's great; oy vey! But I should mention I'm the only "official" blood banker in my lab as well as being the supervisor; everyone else rotates in and out. Any thoughts, suggestions, anyone else having this problem??

If I understand the scenario, you are getting a Positive Antibody Screen on the Echo, but Negative Antibody Screen when tested manually with tube technique. (What enhancement media are you using for your tube testing?)

You say you are getting 2+ to 4+ Anti-D pattern......I assume you mean when you do an Antibody Identification on the Echo? If this is the case, we've had our Echo two years and we see this scenario fairly frequently in patients who have recently received Rhogam. (The Echo characteristically enhances weak Rh antibodies.) We report out these findings as "Anti-D, likely due to recent administration of Rh-Immune Globulin." (And we do not do any tube testing in this situation.)

Donna

Donna,

we don't do antibody ID's on our Echo yet, though because of this scenario, we're looking into it sooner than we had planned. What we get is a positive initial antibody screen that comes up AT LEAST 2+ on SI and SII (lot #R099 Capture-R strips) and most often 3 or 4+. We use ImmuAdd as our enhancement. If the doc orders an antibody ID, most often it comes back negative because our reference lab uses PEG and it won't pick up Rhogam-induced Anti-D most of the time. By reporting when the patient got Rhogam and the results of BOTH methods, we're hoping to cut down on how many ID's are ordered on these patients. Our comment that we send with the reports does also state that the automated screen shows "presumptive Anti-D patterning".

I think you are handling it the best you can at this point.

Regarding Antibody ID's on the Echo, you will probably see enhanced reactivity for many antibodies, particularly Rh and Kidd antibodies. (Also, unfortunately in my mind, Warm Autoantibodies.)

We see a decrease in Cold Autoantibodies (but some still show up) with the Echo. You will probably see some "trash" that you can't identify (similarly to how we sometimes see "trash" with PeG that we can't identify.)

It is not my intent to prejudice you when you do your validation studies for Antibody Identification on the Echo, but rather to remind you that your Echo Ab ID test results will not consistantly match your tube results. So when you evaluate your validation findings, you need to consider/decide you will consider to be "acceptable" for your lab. (You can't beat the ease of throwing an Ab Id on the Echo!)

Donna

Donna, thanks for your comments! It's nice to get some positive feedback from someone; this issue has been a real thorn in my side. I'll keep your thoughts on the Echo Ab ID's in mind. It will most likely be after Jan. 1st as we're in the middle of converting our computer systems and I'm in charge of building and validating the blood bank dictionaries; yikes!

With a large L&D service we see this a lot. If Rhogam was administered within 90 days we report out "Anti-D passive, probably due to RhIG." I have found that using PEG enhancement in tube method correlates better to the Echo when picking up the weak RH antibodies.

D.C. -

Been there, done that.....Actually doing that now (validating some major computer upgrades.) For me, it's like "yuck!" than "yikes!" Anyway, good luck with both the computer and Echo Ab ID projects.

Donna

I use gel and we see the same phenomenon - antenatal RhIg shows up for up to 12 weeks post-administration. We run a selected cell panel of 5 cells and report out anti-D, probably reperesents residual antenatal RhIg. We recommend repeat in 3-4 months after the last dose . . . our OB docs have never followed up on this.

We do the same as David and after checking on the RhoGam status, report it as:

"Anti-D, passive due to RhIg administration"

Ah...yes....the ECHO. The little fella who's so sensitive if you look at him sideways, he'll cry?

He has always been like that with us. Totally supersensitive. It took a while and lots of money down the drain with time and reference lab. charges but we finally did decide to do all positive screens from the ECHO on the bench in Liss and that's our answer. 99% of them are negative. There are some ECHO owners who work up all the positive results. We don't have that kind of staffing. Our last AABB inspection was with flying colors and the inspector totally agreed with our procedure regarding the ECHO postive screens. So, there ya have it. : )

As always, different techniques are out there. Both Solid phase and gel are very sensitive for picking up Rh Immune globulin anti-D. We do a manual gel panel and get the Rh Immune globulin history and make the comment likely due to the injection. We do not send ours out and do not do a tube panel.

Would love to have you all come to the aabb RAP session on Family Fued: differences in gel, glass bead, solid phase and tube, and share your cases with everyone, if you are attending the meeting.

marilynm

We have a provue which is an automated gel testing instrument for blood bank. We also get pos OB screens up to 3 months after Rh Immune Globulin is given. If pos screen, we then do a "mini-D" panel manually...just 3 to 4 cells with an autocontrol to show there are no additional alloantibodies. If neg, we report out anti-D due to RHo(D) Immune Globulin injection given on ....date. L

We do our Rh negative OB's manually by gel due to this problem. We are also seeing two or three times a week all cells 3-4+ positive antibody screens, and all cells 3-4+ pos on the panel. Now instead of doing a panel on the Echo, we repeat the screen with gel and if negative report that. During go live we saw this on a patient with a history of Anti-E. Our specialist called it into Tech Service to see if they wanted the sample and was told it was a sample problem and not an instrument problem. When I told them I was recommending to my Techs to repeat by an alternate method, he told me that it was a good idea. Mary

I'm curious, are you doing the prenatal and antenatal work up on most of your patients? If you are and the antibody screen was negative on both occasions why are you doing an antibody screen postpartum? You know they have had RhIG at 28 weeks, you know you are going to issue them more RhIG regardless of the postpartum antibody screen results so why bother with the third antibody screen during this pregnancy other than "that's the way we have always done it"? In my previous life we dropped the postpartum antibody screen if we had a history of this patient during this pregnancy that showed negative antibody screens up until the 28 week RhIG. All we did on these patients was confirm the Rh status of mom and babe.

We do some of the prenatals, not for the biggest OB group. We do a T&S on all admissions to the L&D in case blood is needed when one crashes and blood is urgently needed. Mary

For Passive anti-D, we see the same thing with our Echo... Positive on Echo and with gel, but negative with tube. However, I would be very careful about assuming the Echo is giving you false positives, just because the tube test is negative. We have found anti-Fya, anti-Fyb, anti-Jka, anti-S, and anti-E all positive on the Echo, but negative in tube.

Donna,

we don't do antibody ID's on our Echo yet, though because of this scenario, we're looking into it sooner than we had planned. What we get is a positive initial antibody screen that comes up AT LEAST 2+ on SI and SII (lot #R099 Capture-R strips) and most often 3 or 4+. We use ImmuAdd as our enhancement. If the doc orders an antibody ID, most often it comes back negative because our reference lab uses PEG and it won't pick up Rhogam-induced Anti-D most of the time. By reporting when the patient got Rhogam and the results of BOTH methods, we're hoping to cut down on how many ID's are ordered on these patients. Our comment that we send with the reports does also state that the automated screen shows "presumptive Anti-D patterning".

We report Labor and Delivery specimens (or any other we can verify recent rhogam administration on) showing Anti-D specificity as "Passive Anti-D presumably due to Rhogam administration on (insert date).

We don't waste our time with doing a panel to ID. It works well for us. And for our patients who probably don't want an added antibody ID charge for something that is expected to be present anyway after RhiG injecton.

Hi jcdayaz,

Do you ever issue blood on these L&D specimens that you report as "Passive Anti-D presumably due to Rhogam administration on (insert date)" with out doing a panel to ID or do you do a panel if they require transfusion?

JB

Hi jcdayaz,

Do you ever issue blood on these L&D specimens that you report as "Passive Anti-D presumably due to Rhogam administration on (insert date)" with out doing a panel to ID or do you do a panel if they require transfusion?

JB

To be honest, that's a good question. Any patient who has received Rhogam is obviously Rh neg and we would be transfusing Neg units anyway. I do not know of any patients who meet these criteria who have required transfusion.

If the pattern of the antibody found on initial testing does not fit the pattern of an Anti-D then a full workup is performed. We look for time since last Rhogam, strength of reactions, etc, etc. If ANYTHING looks suspicious at all, a full work up is performed.

We do pretty much what David does with the RhoGAM problem. Echo panels are very slick, though, and the RhoGAM anti-D will ID nicely.

We switched to PeG for tube testing once we went live with the Echo. My experience from my validation studies was that LISS was too different (weaker) in it's ability to enhance antibody reactivity as compared to solid phase for many of the samples I used. We missed too many real live clinically significant antibodies with LISS that were picked up by the Echo. Peg has always been our go-to method for weak antibody ID, RhoGAM anti-D included, so I made the switch to PeG for all testing. I feel much better about calling an Echo reactive screen negative after getting a clean screen with PeG.