Clarest

Thanks to you all for your reply. Since our main testing method is solid phase which is either Galileo (NEO in future) or manual Capture, the backup method will be mainly used for the issue of panagglutination with solid phase (or it says solid phase dependent antibody - SPDA). Moreover, autoantibodies are not uncommon in our patient population. I would love to have both tube PeG and LISS, but the reality does not allow us...

Hi AMcCord, What is N-Hance? Is it different from saline IAT(no enhancement)? Thanks.

It sounds like tube PEG is not good for warm auto and colds. However, if tube LISS is used as a backup method for solid phase (Capture-R), the difference of sensitivity is bigger than that betwen tube PEG and solid phase. What could be the cons for this combo comparing with tube LISS and solid phase? Could you please let me know your experience? Much appreciated.

Hi all, We're moving to our new site in less than half a year. Along with our move, we're going to start with a new NEO instrument. At the same time, we're going to get rid of the manual gel testing system. Currently, we use Galileo, manual capture-R station and gel system. Either Galileo or manual capture-R is our primary testing method (for antibody screen and the first panel), and gel is our backup method which is mainly used for selected cells and repeating antibody screen/panel. Especially, when all solid phase (capture-R) screening cells and panel cells are positive with a negative DAT result, we repeat the antibody screen/panel by manual gel method and if the result is negative, we suspect the reaction could be caused by solid-phase dependent antibody and conclude that "all common clinically significant antibody ruled out" with the use of saline IAT crossmatch when transfusion is required. Right now, we're looking for a new backup method after phasing out the gel system. Options for us are tube saline IAT, tube LISS and tube PEG. Tube PEG method had been tried before my time and I was told that it's difficult to interpret the result for generalists not blood bankers. However, I heard that tube PEG has the closest sensitivity to solid phase (Capture-R) in the above tube methods. I was asked to do some survey or research on what other labs use as a backup method for solid phase (Capture-R) and what the pros and cons are based on their experience. Please, please give me your inputs. Thank you in advance. Clarest

Could anyone please share a good procedure on how to do a thermal amplitude test?

Hi Malcolm, It's me again. When you said "If it reacts at 30oC or above, it is almost certainly clinically significant, and then it may be worthwhile doing a titre", did you mean do a titre at 30C or 4C? Thank you.

Hi Malcolm, As you said, if we do the thermal amplitude and it reacts at 30C or above, can we just do a titre at 30C? Our current policy is doing the thermal amplitude first, if it's positive, we do the titre at all temperatures which have positive reactions. For example, if the thermal amplitude test shows positive reactions at 30C, 22C, 15C and 4C, we have to set up one set of titres for each of the above temperature. Sometimes, our technologist has to set up more than 60 tubes for a cold agglutinin titre. The procedure is tedious and does not make sense at all !!! The hospital I previously worked for has a different cold agglutinin policy which is after the thermal amplitude test, do the titre at the highest temperature which has positive reactions. However, the highest temperature could be 4C, 15C, 22C, 30C, 32C or 37C. Do you have any reference that I can use it to convince our medical director to change our policy? BTW, our medical director is not specialized in transfusion medicine. On the other hand, in 17th edition of AABB Technical Manual, on page 923 under Method 4-7 Cold Agglutinin Titer Procedure, it says that "Cold-reactive autoantibodies, if present at very high titres, may suggest a pathologic cold agglutinin disease. This may result in overt hemolysis and systemic symptoms and may indicate underlying B-cell hematologic neoplasia". This procedure describes the test done at 4C. I am confused as it seems like 4C titre is very important for clinical purpose, as well.

Thanks to you all for replying my post. I actually called the manufacture regarding the reaction strength after adding check cells and they said we should expect at least 2+ reaction. Then, I asked them for a reference for that and haven't got back from them. Regarding the temperature of reagents, I think it's very hard to practice in reality. If I ask my staff to make sure the reagents reach room temperature before adding them to test tubes, they would probably just leave the reagents on the bench all the time. They are busy and within one shift they may need the reagents several times. I really cannot expect that every time they remember to bring the reagent out of fridge 20 minutes before they add it to the tube. Right now, we have two racks of ABO/ Rh reagents and alternately use them on different shifts, but not able to do this for Ab.screen or panel cells reagents.

I was checking the insert of Checkcell (weak) for revising our SOPs and found that it does not specify the reaction strength after adding Checkcell for validating the test. I don't know where I got this in my mind that in order to validate a negative DAT or IAT test, after adding Coombs Control cell (Checkcell?) the reaction strength should be at least 2+ or above?! I also went to check the insert of AHG reagent and it says that any negative or weak positive result obtained after using AHG reagent should be validated with IgG-coated cells, although they didn't specify how weak is weak pos (less than 1+?). I want to know how many of you add IgG-coated cells (or Coombs control cells or Checkcells) to weak positive DAT/IAT test? Regarding some of other cell reagents, their inserts mention that "Store (the reagent) at 1-10C when not in use". Does it mean we do not need to warm up the reagent to room temperature before using it for the test? I am just wondering where you put your routinely in-use reagents (always in the fridge?). How about the antibody screen/panel cells reagents? Do you always warm them up to room temperature before use? Thank you for your input.

Hi dmpollock, I am wondering why you were only concerned about immediate spin crossmatch. How about full crossmatch for patient with alloantibody(ies)? Right now, the hospital where I work does plasma separation from cells on all samples. Most of the samples received in Blood Bank are tested within 24 hours. However, the samples are kept in the fridge for 1 month here if patients have not been transfused or pregnant in the last 3 months. Because of the practice of separation of plasma, before the technologist performs crossmatch on previously separated samples, they need to do a reverse grouping check by testing patient's plasma with A1 and B cells to make sure there is no error during separation. I really do not like this plasma separation practice, but if I want to eliminate it, I have to prove to them there won't be any impact on test results. In the hospital where I previously worked, the maximum time of samples that can be kept in fridge as pre-transfusion samples is 21 days. However, we separate plasma for Pre-admission patients and for those with alloantibodies. My main concern is that towards the end of one-month period, if the plasma without being separated from cells is still good for crossmatch. I would appreciate any inputs. Thank you.

Recently, we had a 49 years old female patient with leukemia and pancytopenia. In the past three months she had only been transfused with 6 unit of platelets at our hospital. According to the nurse, she had no red blood cells transfusion recently. She had not been pregnant. Last antibody screen was negative on Aug.25, 2014. On Sept.15, we received another sample and anti-E was detected from her sample. We could not figure out why this patient developed antibody. Could this anti-E be a passive antibody due to platelet transfusion? The reaction strength was 4+ with MTS panel. Another strange thing is that the tech. first did antibody screen on Galileo and got positive result. Then she did manual capture R panel which looked like anti-E and anti-c (patient's phenotype is E neg and c neg). The second technologist continued the work with setting up a MTS panel and it looked like a straight forward anti-E. Due to the discrepancy from these two methodologies, we did the third panel on Galileo and it came out as only anti-E. As I know, the first tech. who got anti-E and anti-c was dealing with another patient at the same time. Coincidently, her 2nd patient has the history of known anti-E and anti-c. However, the tech. sad she is 100% sure that she didn't mix up the two samples and actually the results (reaction strength) of two panels from these two patients looked a little bit different. My questions is that in your facility, if a patient developed anti-E and you know the patient is also c antigen negative, do you give the patient E- and c- negative blood or only E- negative unit? Sorry for the long post. Thank you.

From our antibody rule out policy: If the pattern suggests: 1) a single antibody specificity, then rule out is based on a minimum of ONE negative homozygous cells; 2) multiple antibodies / autoantibodies, or there are ambiguous or unexplained reactions, then rule out is based on a minimum of TWO negative homozygous cells. To be honest, I am not quite sure about the reason of TWO negative homozygous cells needed for point 2). Not long ago, in order to meet that requirement, one of our technologists had to do selected cells from other two different panels to exclude two antibodies although the 1st panel already had one negative homozygous cells for each antibody. Does you lab have the same policy? Could you please explain the difference between 1) and 2)? Thank you.

It happened to us last week when a unit of packed red blood cells was returned to us. The unit was out of blood bank for less than 30 min, however, the temperature of the unit itself was 14.5C. We checked our provincial standard (in Canada) and it states that the unit can be returned back to inventory if the unit is out of temperature-controlled area for less than 30min, or the temperature of unit is between 1-10C. So, we decided to accept the unit back to our inventory. Any other thought on this practice?

We follow the following transfusion policy for our Sickle patients: -without alloantibody: give ABO compatible, Rh-and K- matched rbc; -with alloantibody (ies): give ABO compatible, Rh-, K-, Kidd- and Duffy*- and S-matched rbc. *A guide from our reference lab states that that it's not necessary to give Fyb antigen neg. rbc based a theory that sickle patients won't develop anti-Fyb due to gene mutation. However, I did see at least two sickle patients developing anti-Fyb so far. Could anybody clarify this? Is that true more anti-Fy5 than anti-Fy3 is seen in black individuals? Does that mean more anti-Fy5 seen in Sickle patients than anti-Fy3? Thank you.

Thank you jayinsat. Our LIS Coordinators sound like they hesitate to change the time setting for auto transfuse. Actually, I couldn't see any impact on outcomes.

Hi all Meditech users, I am wondering if you have a solution for products that go out in coolers not auto transfusing before the nurse has a chance to use them. Thank you,

Hello all, My question is mainly related to Meditech, not TAR. I am wondering if you have a solution for products that go out in coolers not auto transfusing before the nurse has a chance to use them. Thanks.

The guideline says "Test polyspecific and anti-IgG reagents against IgG coated cells, C3 coated cells and unsensitised cells at time of use or once daily as applicable". Although to me the guideline is not very clear, my interpretation to it is that for polyspecific reagent, we can test it daily against IgG coated cells (supposed to be positive), C3 coated cells (supposed to be positive as well) and unsensitised cells (such like commercial antibody screening cells - supposed to be negative) as daily QC. For the mono-specific anti-IgG and anti-C3d reagents, since we do pos. control and neg. control along with patient samples at the time of use, we do not need to do daily QC for them. Does anyone agree with my interpretation regarding this issue? Could you please share the policy regarding this issue in your facility? Thank you.

Thank you so much Malcolm.

If PRBC unit and HLA-matched platelet unit are leuko-reduced, the residual leuckocytes should be similar in both of them (<5x10^6/unit - AABB technical manual). According to the theory of graft vs. host disease, I guess giving HLA-matched platelet has much, much higher possibility to cause graft vs. host disease than 1 in 9?

I am wondering if daily QC is needed for DAT and weak D test if we perform the test as following? DAT: Poly-specific - patient's tube plus saline control tube; Mono-specific: patient IgG / IgG pos. control / IgG neg. control patient C3d / C3d pos. control / C3d neg. control. Weak D test: patient anti-D tube plus Rh control tube. In the facility I previously worked for, we did as the above and did not do daily QC; but where I currently work, we do daily QC, as well as the above. Is it necessary to do both? Need you input and if you can provide references regarding the issues, it will be much appreciated. Thanks.

Thank you Malcolm. As I checked with reference books, group A2B reaction strength against anti-A1 or A1 cells is usually weaker than 3+. So, I felt a little bit confused with this case. Moreover, could you please explain what kind of situation / underlying disease may cause patient develop clinically significant anti-A1 reacting at 37C? How should the thermal amplitude test be performed, e.g,time duration at 37C, any controls? Thanks.

If the patient is given HLA-matched platelet, the unit of platelet needs to be irradiated to prevent graft vs. host disease as irradiation inactivates T-cells in the donor unit. For PRBCs, it's not necessary to be irradiated. Using leuko-reduced PRBCs can reduce the risk of exposure of CMV, cannot inactivate T-cells.

Recently, we had a patient with following ABO group test result: Anti-A: 4+ , anti-B: 4+, anti-A1 Lectin: 0, A1 cells: 3+, B cells: 0, A2 cells: 0; DAT: neg; antibody screen: neg. I am wondering if this patient is a real group A2B as I thought usually A2B is only 2+mf with anti-A and 1+ with A1 cells. Patient has no history of BMT, but has liver and kidney failure. I told my tech to give group O red cells, group B platelets (no group AB available) and group AB plasma. Can anybody give another thought? Thanks

We actually received more than two samples from this patient and the results are similar.