kharbert

Hello, Diana, I bet you get a lot of these responses, so here's another: could you also share your SOP with me? kharbert@hsc.wvu.edu Thanks, Kerry

I would like to ask if we can clean up our terminology. Due to the legacy of Rh testing history, we continue to use the term "Rh control" for what is now truly a monoclonal control for those of us using monoclonal reagents. Antisera package inserts instruct us to perform a monoclonal control any time the blood type is presumably AB positive. The requirement to perform a control when patient testing yields a presumed AB positive result is because ALL of the cell testing (with Anti-A, anti-B AND anti-D) is suspect because we can't know whether the agglutination reactions were the expected antigen:antibody reactions, or if the cells agglutinated for another reason. We then run a monoclonal control--a solution identical to the A, B and D antisera, but without added antibodies. The monoclonal control in this situation, then, is a control for the A, B, AND D testing, and is not an "Rh control". A positive reaction with the monoclonal control invalidates A, B AND D testing because it demonstrates that the cells agglutinate in the absence of antibodies. Thanks, don't mean to rant, but our history, expertise and extensive experience is getting in the way of accurate terminology in this instance.

I went to an Ortho-hosted workshop 2-3 years ago and they addressed the pos screen, negative panel issue. Their advice centered on the possibility that the problem is deterioration of the screen cells, so they recommended not leaving the cells out on the counter for more than a set time and protecting the cells from light. I don't remember the particulars, but the attendees who had adopted those practices thought that they helped. Would Ortho be able to give you details? (But I'm guess you already contacted Ortho) Oh, so sorry and embarrassed--I just saw that my post duplicates the previous one. Apologies!!

I taught a very basic college freshman intro to med tech course and used a book called "Blood, the River of Life", I think it was produced by the American Red Cross. Sorry- this may be another referral to an out-of-print source. It was truly basic and written at a level appropriate for high school student. I think Harmening or Daniels would be too advanced. I don't like reading Harmening myself--writing style too tortured.

Two more observations about gel frommy experience in student lab: gel uses much lower volumes of patient sample, and the weight of biohazardous waste material is markedly reduced. I also agree with the precautions about using the screen cells. Also, early in gel marketing, anti-E's were missed if using manufacturer's 0.8% screen cells, but 0.8% screen cells created in the local laboratory by diluting 3-5% screen cells were able to detect the antibody. Presumably a problem with the preservative. Another student lab observation: in tube testing, technique is so sensitive and important (don't resuspend cell button too vigorously/don't take inordinate amounts of time resuspending--don't make your cell suspension too weak/ don't make it too strong--etc). Gel testing frees you from some of these variabilities in technique so that you can focus on problem-solving and concept development. This observation probably also applies to training of laboratory staff. Technique in gel is still very important, just not as sensitive and subjective. I'm a fan.

I have seen markedly increased myoglobin levels in patients with an MI. That would explain the funny plasma color and the hemoglobinuria (myoglobin also gives a positive blood reaction). Doesn't explain the bili or the dropping hgb, but it is something to think about....

Here's an article describing clinically significant antibodies (Anti-D, for example) that weakened or disappeared with the prewarm technique: Weakening or loss of antibody reactivity after prewarm technique Regina M. Leger and George Garratty I Volume 43, November 2003 TRANSFUSION To be sure, the authors did not prove that any of these patients would have had a transfusion reaction if given blood based on the false negatives prewarmed caused--but with all due respect to Malcolm (and the respect due is considerable)-- is that a valid standard? It seems to me that that would be very very difficult to prove for many blood bank practices.

Do I remember correctly concerns about SDP plasma because the process destroyed factor C (or was it S, or both?), and recipients therefore were at risk for blood clots?

In my student lab, I used the others previously mentioned and also the Sartstedt Tube Segment Opener. It is white,and uses a needle in the middle. I think it was at least 1/5 the price of the Hematype. Students liked it just fine, occasionally they would miss the little needle and have to try a second attempt at piercing the segment. Not a big deal. Sarstedt Order no. 92.1000 Sarstedt, Inc PO Box 468 Newton, NC 28658-0468 tel 800-257-5101

I think I followed a link from the TraQ newsletter, or maybe a hit on a Google search?

Discrepancies between tube and Galileo D typing results were discussed in a previous thread. Series 4 and 5 and the Immucor tube Anti-D defiinitely use different clones. What if these discrepancies are due to different epitopes expressed on partial D cells that are being picked up by some clones but not others? Seems that we would want to call partial D cells Rh negative. Immunohematology published a comparison of commercial anti-Ds and found that they had very different reactions with different partial Ds. The references were cited in the Galileo thread.

Thank you, John for bringing this up! I wonder about the same thing. I got a stunning 2 minutes of silence when I asked about this at an ASCLS meeting. I believe one of the fatalities reported to the FDA in FY 2005 was due to an A patient receiving O apheresis platelets. (Fatalities Reported to FDA Following Blood Collection and Transfusion. Annual Summary for Fiscal Years 2005 and 2006) Also, according to this article, there are places that only transfuse ABO compatible platelets. Mark K. Fung, MD, PhD, FCAP; Katharine A. Downes, MD, FCAP; Ira A. Shulman, MD, FCAP. Transfusion of Platelets containing ABO-Incompatible Plasma a survey of 3156 North American Laboratories Arch Pathol Lab Med—Vol 131, June 2007 Good question, John!

One of our clinical affiliates uses the Galileo, and they have encountered the same situation: Rh negative on the Galileo and 4+ Rh positive in tube testing. Immunohematology published an article in 2005 about FDA approved anti-D antisera and partial D cells. The citation is: Judd WJ, Moulds M and Schlanser G. Reactivitily of FDA-approved anti-D reagents with partial D red blood cells.Immunohematology Journal of Blood Group Serology and Education. Vol 21, 2005 It appears from their results that partial D patients could expalin the variability of reactions with different antisera, but these situations occur fairly frequently in our laboratory, perhaps too frequently to be explained by partial D. If these situations DO represent partial D patients, wouldn't typing them as Rh negative make sense?

I work in a Medical Technology program, and don't actually work in the laboratory, but one of our clinical affiliates uses Capture. They noticed when doing manual Capture that the package insert recommends incubation times between 15 minutes and 1 hour. When they started using Capture, they used a 20 minute incubation. The techs noticed that sometimes an antibody would not show a distinct pattern on the 20 minute incubation, but after 45 minutes incubation they could identify the antibody. They also learned that it is absolutely essential to be sure that the sample is well-centrifuged and that the plasma is truly platelet-poor. Platelets in the plasma give that fuzzy button look. Kerry

I tried the calculator against my manual calculation and they agreed. The CAP Today article that announced the calculator was pretty scary. Lots of miscalculations were reported. This brings up a question: I have discovered that not all of our clinical affiliates calculate the % fetal cells the same way. Here's how our method works here with an example: fetal cells 200 adult cells 2200 TOTAL cells 2400 % fetal cells = 200 fetal cells/ 2400 TOTAL cells x 100 = 8.3% I think some of our affiliates use the number of ADULT cells, not the TOTAL number of cells as the denominator. I'm wondering how other facilities do this calculation?