labgirl153

Situation for which I need input: My small lab uses the Ortho gel methodology, When we encounter positive reactions with all 0.8% screening and panel cells in gel (including auto and DAT), we then run a panel (Immucor) in tube (LISS) to compare results before sending out to ARC ref lab. Sure, gel is more likely to pick up warm autoimmunes than the tube method, but if the LISS panel is negative and we send out to ARC, they can't duplicate our + gel results because they use the tube method exclusively. Because of this, we go with the negative tube method results and perform full x-matches in tube. If the patient hasn't been transfused in the previous three months, we get a meds list, determine what the likely culprit is and document it. If recently transfused, we perform an acid elution (in tube with LISS) and run against a panel to ensure no alloantibodies are showing up. This works fine and our patients have no problems. However...we have a new tech whose experience from elsewhere has her perform the elution in gel and if all cells are positive in gel just as the initial workup was positive, she documents this as a warm auto with no specificity, regardless of how the tube method comes out. (And at her former workplace they performed their own adsorptions). If the ARC holds to the tube method as their standard (at least in my region), then this might tell me one of two things: a) If it doesn't demonstrate in tube, then it's not a big deal. If a patient's plasma is consistently positive in gel but is negative with another method, then isn't it possible that the patient is reacting to something intrinsic to the gel method (antibiotics, preservatives, the gel matrix etc.) and that the positive DAT (via tube method) is more likely to be simply drug-related and not a bona fide warm autoimmune antibody...or at least not a significant one? I've not seen much on this subject elsewhere, and I'd like to read what others have to say who are experienced in using gel methodology.

Here too, is an abstract comparing the Accumetrics platelet assays to another product by Helena (the ICHOR). From what I understand, Helena is on more solid ground financially, since Accumetrics has been around <10 yrs. Radiometer once acquired Accumetrics but sold it. :coffeecup http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15815877&itool=iconabstr&query_hl=2&itool=pubmed_docsum

No resolution here yet...the pathologists are mum about it at this point and my dept. is out of the loop. Think a decision will occur during the summer but I have no more info on it. Sorry couldn't be of more help. It's likely you've read most of the papers I've read as well on this subject and particularly regarding the accumetrics system. I believe some cardiac institution in Texas has used and studied the accumetrics instrument, but can't get my hand on their papers right now. There's a Polish paper that was pretty well done too: http://www.kardiologiapolska.pl/archieve.php?vol=60&iss=5&pg=459〈=en When I find the papers from the Texas crew, will post those. Good luck.

True, in vitro complement activation doesn't occur in EDTA plasma (C4 needs Mg+ and Ca+2 ions from serum for this, and besides which, C3 from in vivo activation is the important one from a clinical standpt.)... ...But basically, as noted in the first post, her question has really more to do with interference: that is... will the hemolysis interfere with reading the gel cards? I accept slight to moderate hemolysis in plasma specimens, IF the patient hasn't been recently transfused or if there are extenuating circumstances. The greater concern for me is to have a "baseline" specimen and really has nothing to do with blood bank testing. Is this hemolysis I'm seeing prior to even beginning to test due to a bad draw? or is it a true indication of what's happening to my patient in vivo? We've all seen hemolyzed specimens from patients who are experiencing delayed hemolytic reactions or from patients burned or who've suffered massive trauma or DIC. Since OB patients are prone to DIC stemming from eclampsia and other disorders, if their initial specimen is hemolyzed, it's best to get a redraw...Besides which, it's likely that other labs are drawn at the same time on admission, and hemolysis will adversely affect those labs as well. At various institutions where I've worked in the past, OB depts. and ERs have this problem and they always balk. They need some orientation when they draw their specimens on inserting an IV (that usually takes an act of congress). They're either not placing the lines in properly or they're pulling back too rapidly (if they use syringes). If they can't handle the job, then a phlebotomist needs to step in (that would require another act of congress). When discussing the need for a non-hemolyzed specimen, it's a good idea to explain to them (if they'll listen that is) that we (meaning nursing too) need to know if the patient is truly hemolyzing in vivo or not. This is especially important if a patient is later transfused and undergoes a transfusion reaction...if the pre and post specimens are hemolyzed this complicates matters, even if the DAT is negative. Cutting to the chase... since we can't dictate what nursing does: get a new specimen if it's convenient to, and if not, gauge the degree of hemolysis so far as it affects the gel card reading. Note nursing's refusal to redraw, proceed accordingly.

My past experience is in agreement with BBKdiane's (and she did a great job of conveying it). Whenever a new admission pops in and the physician wants "only" FFP, I take the initiative and request a "type and screen" for all the reasons BBKdiane mentioned...because all of those scenarios occur and they're not rare in the least. ...plus, who wants to perform a screen on some patient's plasma that's been significantly diluted after having pumped several units of donor FFP into that person ... and now they want to infuse 3-4 units of blood to make up for the hemodilution that they didn't foresee? I sure don't. I agree...nip it in the bud at the get-go and if they do have an antibody but don't require packed cells right away, it buys you time to work it up and find units down the road.

The discussion on platelet function assays is still very preliminary at my facility, (i.e. haven't heard of any input from the cardiac folks), but I suspect that several scenarios both within the cardiac dept. and outside it would make such an instrument very useful. #1 Something that's geared toward determining both the baseline of platelet inhibition and inhibition after a patient receives loading doses of inhibitors (abcixmab for e.g.) and a bolus of heparin for PCI procedures and CAGBs is more along the line of what's in store. (Cath lab and cardiac suite) #2 Also, the concern for us as a transfusion service with a limited commodity (platelets) is determining to what degree a patient's platelets have been inactivated when they suddenly need a cardiac procedure while on plavix (i.e. do we really need to transfuse someone with platelets who has a 300k count just because they took plavix and the doc is skittish). #3 Also, a POC instrument for the ED to get a baseline on folks who present with cardiac symptoms would be helpful so far as determining the likelihood of complications in the patient's near future. See refer: Journal of Thrombosis and Thrombolysis Issue: Volume 18, Number 2 Date: October 2004 Pages: 109 - 115 #4 An instrument that tests for aspirin resistance (apparently a significant segment of the population is resistant) Ideally then, testing for the efficacy of plavix therapy plus another assay for platelet alpha granule inhibition would be fairly ideal...especially if these assays can be performed with specificity/accuracy in a rapid, cheap manner. I've reviewed several assays and methodologies comparing one to the other, and while CP (flow cytometry) which employs shear-dependent platelet function testing is superior to all both in terms of following patients short-term and long-term, it's expensive, time-consuming and isn't available 24/7 at most facilities. Aggregometry is also more cumbersome, but the RFPA (accumetrics) is almost as good as what the CP gives when a baseline value is run and submitted as a ratio with the data from the drug-induced inhibition. Fortunately, RFPA can check for the baseline concurrently with the degree of inhibition even though the patient has been on an inhibitor for weeks. See ref: http://circ.ahajournals.org/cgi/content/full/103/11/1488 You mentioned the x and y values of graphing...the RFPA utilizes a different unit of measure (PAU) platelet aggregation units, which can then be translated into percentage of platelet activity (or inhibition). There are set percentages from which the user can determine to what degree the patient requires more or less anti-coagulation and then administer accordingly (i.e. the cath lab). As far as how this platelet function testing translates into determining when a patient might need platelet transfusion and/or if there would be benefit despite other parameters...am still researching this, but believe this is basically covered under the plavix and aspirin patient population. ...still researching this topic...:spotlight :

MUSC (Medical Univ. of SC) in Charleston, SC has their transfusion Service handle the tissue bank...I don't recall the bed # but assume it's >1,000 beds. They've only started this in recent years.

Most the facilities at which I've worked over the years employ some MLTs with some restrictions or no restrictions in the least. MTs normally have the benefit of more theory and training, but ultimately, the true test of competence rests on the individual, i.e. their initiative to read on their own, to seek out additional CE, their degree of confidence level and trouble-solving skills. Also, much of their success rests on the willingness of the supervisor and others to mentor them. Overall, I would say that MLTs perform well in the transfusion service, but are not exceptional. I've also worked with military-trained MLTs who made the transition to civilian life and found these folks to be the least proficient and lacking theory to an alarming degree, (with one exception...an ex-air force guy who was a great blood banker). BTW, although I hold a B.S./M.S. in biology, I'm an MLT (although that will soon change after taking the registry for the BB specialist). I'm also responsible for my department's CE. Over the years, on the way to earning my bachelors and masters degree, I experienced some discrimination during my attempts to learn more and become a better tech, but I attribute most of this to working the off-shifts, where management tends to ignore workers, instead, grooming dayshift folks for educational opportunities and promotion.

Has anyone here been assessing platelet function assays for their cardiac patients and other patient populations of late? Our cardiac dept. and pathologists are considering going to a point-of-care instrument or perhaps evaluating a turbidimetric analyzer for platelet function in patients receiving clopidogrel (an ADP agonist), and/or for monitoring platelet glycoprotein IIb/IIIa activity as affected by the meds abciximab or eptifibatide. I don't believe there's much interest in assessing platelet function in patients with von Willebrand's or those of the rarer hereditary platelet disorders, rather just in those taking therapeutic drugs and undergoing procedures where they might require platelet transfusions and other coag factor replacement. Have done some extensive reading on the various assays and instruments, but am interested in knowing what others have evaluated and are using. From what I understand, the PFA-100 (sysmex and dade) is not FDA-approved (no medicare reimbursement?), but there are several instruments out there (Chrono-log and Accumetrics), and their various evaluations look promising. Normally, this sort of item is the province of the coagulation/hemo dept. but many transfusion services/blood banks have a closer relationship with the cardiac people so this assay might fall into our lap. :coffeecup

Thanks Dawn and Christie...for these additional clarifications. Will be sure to pass them along. I wasn't too keen on the idea of diluting antisera both for the reason you listed Christie (unique diluents for each antisera), and also because of the added burden of establishing the degree of dilution for each antisera. The information the two of you have given is more along the lines of common sense.

My facility performs weak D testing on cords only, but this was implemented only recently. It's been well received for the most part. Most everywhere I've worked in recent years has dropped the weak D testing with little or no negative comment. The only problem encountered thus far was the case of a woman who had always been typed as weak D positive via reference lab and previous hospital stays, but now, as a result of the new protocol, she was typed as Rh negative. She had just delivered her sixth child (Rh pos like the previous five). The frustrated OB had us switch the type back to "weak D pos" because, he wasn't about to change her type after six deliveries and start her on Rhogam, when "she'd never needed it previously" (antibody screen is still negative). Of course, she might have just gotten lucky all the previous times or perhaps she was group O and the babies all either group A or B, which would have allowed her immune system to swiftly destroy the A or B fetal rbcs before her immune system recognized the foreign D epitopes and responsed to it.

I appreciate all the responses on my original question, especially John's question and Lcsmrz's answers leading up to Sheryl's links to the FDA documents. My lab will perform negative controls as well as positive controls for the outdated cells (I forgot to mention this fact previously). I'm somewhat unclear as to Sheryl's statement for the use of dliuted monoclonal antisera. I'm assuming Sheryl means using diluted antisera only against those cells used as positive and negative controls and NOT against donor and patient cells, where we follow the insert instructions for each antisera we use. :coffeecup

You bring up a good point concerning the validation of patient-derived antisera. There are guidelines but nothing is set in stone. For instance: BCSH guidelines published in Transfusion Medicine 1996;6:273-283;... 6 months (shelf-life) for separated serum or plasma at -30 C. Currently, our aliquots are stored at -30 C and it would prudent to stipulate that each aliquot can only be thawed and used once, vs. repeated thawing/freezing. From the literature, I believe the concern over lability of IgG antibodies is mostly due to the repeated thawing/freezing and not the actual storage process. Some studies have been done more recently so demonstrate the good stability of IgG antibodies in unpreserved, human plasma but more needs to be done. (Here's one study: http://cdli.asm.org/cgi/content/full/10/1/19). In practice we freeze and thaw aliquots for antibody titers in prenatal patients over the course of their pregnancy and yet never read where this is a validated procedure...except that prenatal plasma isn't used to test reagents or used in the identification of antibodies for other patients, so perhaps it's exempt from stringent validation. As far as validating our plasma aliquots for activity, we could do this by testing an aliquot each month against a panel of cells heterozygous for the specific antigen (let's say 10 cells) to ensure activity and to devise an SOP for this purpose.

Recently, a discussion at my facility occurred over QC' ing expired panels used for cell rule-out in antibody work-ups. Tentatively, it's been decided to keep panels for no longer than one month beyond their expiration date, while retaining a few select cells expressing rarer antigens or unusual phenotypes for more complicated work-ups. This gives us six panels to work with at all times (four 0.8% cell panels from Ortho, two 3% cell panels from Immucor), and a handful of vials that we retain for no more than 3 months beyond their expiration. My supervisor believes that when QC' ing expired cells, these cells should be tested against stockpiled plasma from previous patients having a known antibody (strong enough to detect heterozygous expressions) versus using commercial antisera alone to ensure that the antigens are intact for agglutination and detection. The reasoning behind this: Monoclonal antisera is purer, perhaps of a higher titer, and might react even with cells having significant deterioration of antigen expression ...but against patient's plasma, the antigen expressed on the “old†cells might miss detection for a number of reasons all related to the complexities and variabilities of human plasma. In other words, we want to QC with commercial antisera, but also use antisera that is nearly identical to the patient matrix. Right now, we're freezing aliquots of plasma from our patient population for as many antibodies to single antigens that we can (it's easy and cheap too). We intend then to use this in combo with the commercial antisera when QC' ing these expired cells. Question: what is everyone else doing and is there a regulation regarding this practice? :juggle:

Albumin...central supply Clotting factors...Transfusion Service Rh immune globulin...Trans. Service WinRho...Trans. Service IVIG...Pharmacy

Gel methodology has been the prevalent technique for most of the facilities where I've worked these past few years. On occasion, have encountered cold antibodies showing up even in gel...these having a diffuse pattern and variable reactions. Employing the prewarmed tube method with LISS has taken care of most cold antibodies in my experience and I've not yet see any conflict between my results with either previous workups or with specimens collected later and worked up by co-workers or at reference labs. But since I'm no expert! for those interested, perhaps another voice would be helpful: "Applied Blood Group Serology" (Issitt, Anstee) 1998, 4th ed. pp. 881-882. Issitt states that if the pre-warmed technique is missing significant antibodies, then perhaps that's due to a lack of potentiator in the incubation phase vs. something inherent to the technique itself. In earlier AABB technical manuals, the prewarmed technique omitted a potentiator, whereas in the most recent (15th ed.) pp. 691-692, a note was inserted suggesting the use of a potentiator (LISS, albumin or PEG) with the caveat that cold reacting antibodies might be potentiated along with any significant antibodies.

hermaphrodite.

I agree with you Donellda...it's best to go with the Rh pos unit and "worry" about the exposure to the D antigen later. I'd hoped this would have been the normal response to my theoretical scenario but among a couple of folks I quizzed this was went too far against what they've had preached to them in the past. In my mind, it comes down to immunology vs. "protocol" and I would hope that folks would think through this i.e. what's happening in vivo and have some understanding of immunology before turning away what is best for the infant. We tend to think of immune response in terms of what happens in an intact mature system, but in a newborn, particularly a premie, all the steps from recognition to response are huge unbridged steps from T helper to cytokines to B memory cells etc. so exposure to foreign antigens doesn't have the same consequences as it does for an older child. BTW, this same scenario was close to occurring at my facility. We did have a woman set to deliver with anti-E, anti-c who was A Rh pos. And I did place a stat order for a neonatal O Rh pos, E=, c= unit just ahead of the deliveries. Fortunately, the twins who were both of her type and phenotype, neither of whom required blood throughout their stay. The reason for posing this question to my co-workers soon after the real event (and to y'all), was a concern over what if anything a tech would do in a situation where the baby was Rh neg having the "offending antigen" attacked by maternal antibody, i.e. 1) Would they have immediately recognized that transfusing the O Rh neg unit was unsuitable? 2) And recognizing this, would they have understood the immunology behind this enough to have consulted with the pathologist on-call to get a final decision (this scenario occurred late in the evening with a lone tech on a weekend). 3) Finally, would the pathologist (unlikely to be a transfusion specialist) have been given enough time and info in a quick call out of the blue to really consider the right decision? I'm just grateful that we can discuss these situations before they happen so everyone has a chance to think about it and hopefully do the right thing in the future regardless of protocol or what they were taught years before. :cool:

Look over this scenario: A 32 yr. old woman suddenly presents who is A Rh pos with anti-E, anti-c (stimulated by a pregnancy in 2003). She is now set to deliver twins at 34 weeks gestation. No titers have been done and her husband's ABO and phenotype are unknown, although it's safe to assume he possesses E and c since their first baby exposed the woman to these antigens. As a precaution, prior to the delivery, the transfusion service finds a fresh, irradiated, CMV neg, O Rh Pos, E neg, c neg quad unit that is compatible with the mother. Even though the ABO and phenotypes of the infants are unknown, the neonatal O neg unit won't be available for these babies since (as you know), most Rh neg donors are either homozygous or at the least, heterozygous for c. The infants are delivered, cord bloods and peripheral blood show that twin “A†is A Rh Pos with a negative DAT. Twin “B†is O Rh neg with a positive DAT. An elution from twin “B†demonstrates anti-c, but anti-E can't be ruled out. This baby is anemic and the M.D. wants to transfuse within an hour...it's even possible that an exchange will be necessary but right now the physician wants 60 cc transfused stat. The supplier doesn't have any O Rh neg of the r' r' haplotype readily available and certainly not on a stat basis. Quick...what do you transfuse and why? In this scenario, the mother must be R1r' (CDe/Cde) and the father is likely: R1r'' (CDe/cdE). There is a 25% chance of getting an r'r'' child (Cde/cdE) and a 25% chance of getting an R1R1 child (CDe/CDe). The other combinations could be R1r' and R1r'' (like either parent). I put this theoretical question to my co-workers and got some interesting responses, but the cardinal rule is to transfuse what is compatible with the mother and what is ABO compatible with the infant. Also...believe the baby's immune system isn't mature enough to recognize or respond to the D antigen present on an Rh pos donor so...let me know what you folks think.

Have been following this discussion closely now on the pre-admit expirations...my facility is switching from cerner classic to mill too. Am sure this situation with the inflexibility of Cerner Mill. will not make my co-workers and supervisor happy! Currently, with Cerner classic, we can order a test code to extend our pre-admit x-matches to 7 days, but if the patient is drawn on Tues. and gets transfused Thurs. (whereupon the xmatch should revert to 3 days exp. from Thurs.), we have no way of changing the expir. to reflect that (in cerner classic). In the system, the x-match remains at 7 days from the drawing of the specimen. Had hoped that with Millennium, that this and other pre-admit issues would be resolved. Now I see it might not be so. Must admit...I'm also a Mysis/Sunquest fan. And what's with Cerner and the Julian calendar?? Thought the rest of the world has been using the Gregorian calendar for the past ~500 yrs.

Thanks Mary for the input. Hadn't heard about the printer programming situation and this would be helpful to know that there might be an issue. I never cared for the icons, as they rather look all the same and crowd the screen but my experience has thus far been limited to the training modules and from hearsay. I'd rather memorize a few codes and acronyms then do pull-down menus and deal with several windows open at once etc. Just my preference though. Anyone else who has experience with Cerner mill, please also weigh-in...and you also Mary if you can think of further comments.

My facility also performs a select cell panel for these cases, with the disclaimer in the workup of "anti-D probably due to Rhogam" but only if we can document when the last dose was injected. If not we assume the mother has a true anti-D and we go from there (i.e. perform a titer to get a better idea of what we have). We also perform gel x-matches on these mothers if the M.D. orders blood, but don't tie up Rh neg units otherwise. Our dilemma came when we considered performing DATs using the gel methodology on the infants of these passive anti-D mothers. Since gel is very sensitive, it picks up the mother's passive anti-D coating the baby's cord cells, vs. the tube method, which rarely picks this up. We hated the idea of reporting out positive DATs on these infants from gel when we knew it was passive anti-D (not a true D) coating the cells and that it would be of no consequence to the baby. That is, we didn't want to confuse the medical staff with this "extraneous info". Instead, we still perform the cord cell DATs with tube (IgG only) in cases where the mother has been shown to have only a passive anti-D. If there's something significant coating the cord cells, a tube DAT should detect it, so we're not concerned about "missing" something.

I've used many LIS programs over the years...Sunquest/Mysis, Meditech, Hemocare Lifeline, HBOC, Cerner classic and Cerner Mill. (limited exp.), plus some "homegrown" systems along the way. Would like to read input from those of you who've used Cerner Mill. so far as pluses, minuses in the transfusion service and comparisons to what you've used in the past etc. Or, if anyone can direct me to a site or blog/forum that has opinions from a bench tech's and supervisor's standpoint that would be great. :cool:

Thanks for the replies...fortunately, the twins at my institution turned out to be R1R1 like the mother...otherwise it could have been a bad situation. I suspected that anti-c was a major player at times and you all confirmed this. Apparently, the M.D. at my institution was not concerned in the least of what could have been a bad scene. Ahead of time, I ordered an R1R1 irradiated, CMV- quad unit to be shared with both babies just in case of an emergency, seeing that our standard O Rh neg unit reserved for neonates would be incompatible with the mother (since most Rh neg donors are either homozygous for c or at the very least heterozygous). I'm new to this forum and am enjoying the info! Thanks.

When was the last time any here were involved with neonatal exchanges? Do you recall the precipitating factor that led to it? (aside from allleviating hyperbilirubinemia i.e.)...what maternal antibodies do you most encounter that lead up to a possible exchange aside from anti-D? At my institution we've not had to resort to doing one in quite a long time, but we've had close calls of late (usually due to immune anti-D). One M.D. seriously spoke of performing it in a type B neonate (mother was O), but in that case am wondering if he considered G6PD deficiency, since the bili lights did their job within 24 hrs. of birth. Right now we're delivering twins whose mother has an anti-c and most likely an anti-E ... no word yet on the status with the babies or if we will need to transfuse. :cool: