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Posts posted by NedB
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I was working the evening shift in those days, now I am in a position to write the rules, so to speak. What was relayed to me was that he said we proved the screening cells work, but what about the rest of the cells we get. It didn't seem reasonable at the time, but those in charge made it policy. Over time it became in-grained; then when we switched to gel and stopped getting 3% screen cells, but continued to get at least one 3% panel, that panel became the most-used. Now I tend to stay away from screen cells because we've gotten out of the routine of refrigerating them during the day and some of the antigens may have leached. Not entirely logical, I know - so I probably should no longer blame that poor inspector, but he started it, as my kids used to say.
Actually I should apologize for an error in my original reply. We used commercial antisera, not Patient samples to validate the methods. We used panel cells and had each run by more than one Tech on a particular day, a day we happened to need to run a particular antigen for a particular patient. We wanted this spread out over the whole staff and all shifts.
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In the interest of combining 2 processes, why not use the diluted Anti-D you make up for serofuge recalibration mixed with Rh+ cells? We are few enough here that all of us get to do elutions. But I will keep what y'all have said in mind, because I see us having 'Main Lab' people in the Blood Bank in the future.
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When we validated antigen-typing in gel we used Patient samples and tested with "heterozygous' cells. At that time we validated Anti-Jka, -Jkb, -Fya, -Fyb, -Lea, -Leb, -S and -s. Since then Ortho changed the Anti-Jka to a non-AHG protocol; and we no longer antigen-type for Lea and Leb. I can't see the expense of using gel when the protocol does not require AHG. For antigen-typing, sensitivity is not an issue; you will verify with an AHG crossmatch anyway. For our positive controls we insist the Techs use a 'heterozygous' cell. One inspector asked us to stop using our screen cells as controls, so now we try to rotate among the panel cells as much as we can.
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We have an 8-unit thawer, but only fill it up when we must do plasma exchanges or the OR wants both FFP and Cryo. I can not see the need for thawing in anticipation. FFP is for replacement of coagulation factors; there are better blood-volume expanders. We call to verify the order as most of you.
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We use the Igloo-made coolers from Market Lab and validate yearly with 3 chests, one minimally packed, one maximally packed and unopened; and one maximally packed and one unit removed every 2 hours. I wonder what all of you consider the correct limits. If this is defined as transport, 1-10C is acceptable; if this is storage, only 1-6C is acceptable. We don't see a difference among the chests but rotate them for use and for checks anyway.
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Well said John. I came across this sentiment a number of years ago, the author went on to say that universities seemed to be moving in that direction and he lamented that soon universities would be in the same situation as hospitals. Incidentally, your phrasing was succinct; the other author required one bar in a newspaper.
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We have been using gel a good while, and do our AHG antigen typing on gel which is still not endorsed by Ortho; but I don't know about using gel for C3 activity as you describe. Do you incubate 5 minutes first, or is the 10 minute centrifugation your incubation? Do you follow the reading with addition of EC3d cells to control for false negatives? We do tube testing for our DATs because our experience has been that a positive DAT by tube correlates well with being able to elute antibodies from the cells, whereas a positive autocontrol on gel does not.
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The ProVue examines every card before accepting it for testing; sometimes the buffer just above the gel forms bubbles, probably from rough handling. We spin these cards before use and the ProVue invariably accepts these.
As for the re-spinning - not a good idea. Re-spinning the plasma from the sample (preferably in a micro-centrifuge - 15,000+rpm) and investigating for rouleaux are better courses. If the rouleaux does not show, double the volume of plasma and re-check; remember the gel is ultra-sensitive.
Question for Susannah: Do you have the product insert for the Bio Gel? I evaluated it way back but didn't keep the literature. Who knew?
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Our protocol is that daily when we use the QC kit (Ortho's and Immucor's are similar) we take the tube with Anti-D and the AB- cell to Anti-IgG and the check cell. This also satisfies the NERL Blood Bank saline requirement of doing a DAT daily. On testing a Patient for DAT we include a reagent cell to test with the Anti-C3b,-C3d. We have settled on using the A1 reverse typing cell. I can see the temptation to add 6% albumin to test the adequacy of the washing; but that is the purpose of the check cells which you must use anyway.
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We check ours annually also. If you have yours calibrated by Control Company, they will put a re-calibration required in one year label on the thermometer. I send ours off to get it back in time to re-calibrate all our other thermometers in December.
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We use Bio-Logics Identi-print (the label embossing cards). With this system you can let the nurse cut off the arm band to start her IVs or for whatever reason. Supply them with blank bands and they can re-attach a new band and move the card from the old band to the new. If the blank bands are kept handy all this can be done at bedside and no chance of the wrong card being used. We usually can keep the same arm band throughout a hospitalization - and beyond for our outpatient chemotherapy Patients. Requiring a copy of the arm band label to pick up blood satisfies the CAP question trm.41650.
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Or you could just do the titer in gel. Pipet 50 mcL R1R1 cells onto gel cards and add 25 mcL of each of the 2-fold dilutions. Consistency and reproducibilty are key here.
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ckcheng and galvania have both succinctly stated our policy and procedure. Anyone calling a weak D Rh+ and not giving RhiG is taking a gamble. As it is with the strength of reagents in use now, we use a cut-off of > 2+ and don't do weak D except on donors and newborns.
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Negative tests are not required by CAP and AABB. You must test the 'reactivity' of your reagents. Running a 'Negative' DAT would seem to prove nothing.
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When you see a mixed field (cut and dry with gel) the importance is to figure out why. Dual populaions because of different group or Rh transfusion? If this is known and the reason is benign, the strength does not matter. If the reason is not benign (Rh+ to Rh-) you would want to follow the survival of the Rh+ cells - so record the strength. If you are tube testing and this is an antibody screen and are considering Anti-Sda, again the strength is part of the workup and needs to be recorded.
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Must respectfully disagree with David Saikin. True, newer timers seem to have a circuit that makes them stop timing when the battery runs low. This is probably not true of older timers. In addition, timers on plasma thawers and centrifuges are also digital, but you wouldn't not check these, would you? Here we check thawer and centrifuge timers quarterly against bench timers and check the bench timers themselves annually.
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My routine for cold/rouleaux encounters is to add two drops of saline and re-spin. With weaker rouleaux reactions, the clumping is ususally dispersed. If not, I incubate the tubes in a BB refrigerator (top shelf) 2 minutes and re-spin. Increased reaction signifies a cold; I re-set up the reaction using plasma prewarmed in the reaction tube.
If cold incubation reaction did not increase I suspect rouleaux, re-set up the reaction and do a saline replacement. We have capablility of attaching Patient's comments, and describing your results guides the next Tech.
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I mentioned the AABB discussion about probabilities. The reason for the use of probabilities is that most antigens show some diversity (Anti-D in Rh Pos patients). By selecting more than one cell to rule out you reduce the odds of missing an antibody which was stimulated by a single donor with an uncommon or less than common form of the antigen.
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We also have been using gel since 1998 and have a ProVue. We also would not switch back to solid phase or tube testing. Our thinking is that the more sensitive we can make the screening and the AHG crossmatch, the less likely the patient will develop additional antibodies. We do IS XM if the screen is negative. You will not regret the decision to use gel. And yes occasionally you will have an antibody you can not identify easily; but that compatible gel AHG XM will let you breathe easy.
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I think larevalo is asking for acceptable ranges for checking the timers and thermometers. There are no acceptable ranges posted for timers (that I have seen), so we use what is acceptable all over the lab, +/- 5%. We check all timers for this range, timers, centrifuges, plasma thawer. As for the thermometers, we use the AABB criteria, +/- 1 degree for all thermometers and +/- 2 degrees for charts. The simplest way to check timers, of course is to use the nist.gov site. All of our inspectors have accepted this.
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The AABB Technical Manual has a discussion about probabilities for ruling in or out. We follow their suggestion; three cells to rule in or three to rule out to have a 95% confidence level; with the caveat that one homozygou equals two heterozygous. The AABB protocol is basically sound for high- and moderate- incidence antigens, but does not give a mathematically sound 95% confidence level with low-incidence antigens. That said, antibody identifications sould be correlated to the percentage of incompatible AHG crossmatches with supposedly antigen -negative units. If the percentage is high, guess what - you missed something. Incidentally, we use (and love) gel.
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OK this may be kinda long.
We used the Capture R along with Gamma's Stat-Spin ABO/Rh for donor processing for many years. When Gamma stopped making the Stat-Spin available, we looked around for something else and evaluated Ortho's gel as well as Gamma's gel. The Gamma gel was easier to perform but it missed an Anti-Fya, so we opted for the Ortho gel and have never looked back. With the Capture R we would get approximately 3-5% of the run Positive and would then do a 3 cell screen in tube (LISS or PeG) and most of these would turn out to be negative. About 1% of our tests were a true Positive. When we switched to the Ortho gel we only saw the 1% true Positive. We seldom see anything on gel that is not a true and significant antibody. We got rid of our cell washers and went thru a process of validating antigen typings that require an AHG phase on gel, beautiful; and the technique uses only 25 mcL per test. When the ProVue came on the market, we bought the first one in Louisiana. To clarify some of the points in this thread. Yes you can add new samples to the ProVue without waiting for the incubation phase of the preceding test to complete - it's what the 'Emergency Stop' is for (a misnomer in that it really is only a 'Stop'). Why would anyone want to put an Immediate Spin crossmatch on a machine. If you use a screen with high sensitivity like the gel or the solid-phase, the only thing the crossmatch does is verify ABO compatibility - 2 drops of plasma and a drop of donor cells will cost you less than 5 cents, can be done in seconds, and will give you a visual of what will transpire in the transfusion. We have had very few problems with the gel system or the ProVue - but you should have a maintenance contract for the machine. The big reason to automate is cross-training blood bank and main lab staff; but to me this is also a big reason to use the gel. No one has mentioned this aspect, but with the gel dual populations with differing specificities separate on reaction with the corresponding antiserum. Mix Rh Positive and Rh Negative cells and react with Anti-D and you see both populations. This has come in handy more than once.
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Hello Liz, this is Ned B. You may want to mix fresh serum with your plasma and test with Poly AHG and you may want to do the testing in plastic tubes. Anti-Jka loses its complement reacting component if not stored correctly. We have not used Capture R in quite a while so I don't remember much about the system (whether Capture R uses or can use Poly AHG). We use the gel system exclusively and see no discrepant results - is this good or bad? We hardly ever see something in gel that does not turn out to be a true antibody. My last suggestion would be to try typing the Patient with a different Anti-Jka reagent; Ortho's one does not require AHG.
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Actually there are other issues with HCLL. Like you my contact is with someone else's system; we have Cerner, but don't let me start. HCLL has or had a problem with the * in CheckSum. HCLL apparently uses the * as a command, and one in 37 units will have this as a CheckSum digit (the 26 letters of the alphabet, the 10 numerical digits and *). Apparently there is a work-around; so I would contact HCLL to make sure you have the latest and greatest upgrades.
Physician's Acknowledgement Of Risk Form
in Transfusion Services
Posted
We have such a protocol, but call ours an Emergency Release. It is the same form we use when we have to issue uncrossmatched blood because of an emergency. On the form we indicate the nature of not providing crossmatch-compatible blood, acute urgency or least incompatible. We send the top 2 copies of a 3-part NCR form at the same time we send the blood. The physician signs the top copy and sends the second copy back to the Blood Bank. The top copy, of course, is put in the Patient's chart. On return fo the second copy we file it.
I guess my concern is the number of instances you are encountering. We are a 169 bed hospital and do Emergency Releases maybe once ever 2 months. We must do a least-incompatible release even less often.
As you say, this is separate from the informed consent; and no physician has ever refused to sign the statement.