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If all your controls and daily QC are performing as expected, there is no reason to take the instrument out of service. As everyone has clearly explained above - often the issue is sample-related or method-dependent. You'll drive yourself crazy trying to figure out how to re-validate an instrument if the only thing that demonstrated unacceptable performance was the one sample

Please understand that NO ONE method is guaranteed to detected 100% of the antibodies 100% of the time. We have 2 automated machines, 2 semi-automated machines and plain old fashion manual tube testing. We have seen, REPEATEDLY, where one method would detect an antibody while the other one would not. If your instrument failed to call a pos. a pos. then yes there is a problem. If it failed to detect the antibody, then as Anna said, you have to evaluate other possible issues and possibly chalk it up to methodology. Good luck.

But surely exactly the same can be said of manual techniques? There are a whole load of issues within this question. 1. Has you instrument been properly validated, do you carry out routine maintenance, are your daily QC in order, are the antibodies you use in your daily QC sufficiently weak to be meaningful, are you using the instrument as per instructions, are the cells OK, is the samplke fresh, etc etc? 2. Did the instrument miss the antibody because it called a clearly positive result negative? Or did the result really look negative? If it's the first, then the instrument needs to be checked. Or was it a positive, but such an atypical reaction that it is understandable that it was called negative? 3. Did the instrument 'miss' the antibody because it was too weak to detect? Did you repeat with exactly the same reagents manually and get the same result? If you did, then you can't blame the instrument. If, on the other hand, you get a good positive manually and neg with the instrument, maybe you had bubbles on the top of your plasma sample and the instrument pipetted bubbles? Or maybe you didn't mix your cells before putting them on the instrument and it pipetted a cell suspension that was too weak? Or maybe the cells were cold? 4. Why do you say it's a clinically significant antibody? Some systems are more sensitive than others at picking up cold antibodies or anti-xxx-like antibodies than others. What your system 'missed' might be one of these that was picked up unneccessarily by a different type of instrument I think that will do to start with. I get the feeling this will be a very active post!

There is an article in Transfusion, "How We evaluate Panagglutinating Sera" on page 1540, volume 49, August 2009. The authors present an algorithm for panagglutinating sera. Are you familiar with the information in this article and how does it relate to this patient? I am curious about this situation and it completely baffles me, and hope you don't mind answering these questions... Am I correct in thinking that if, in your workup, the patient's serum reacted with 8 of 11 cells, then this is not really a panagglutinin? The definition of a panagglutinin, as presented in the aforementioned article, is an agglutinin that reacts with all red cells tested. Also, you mention that in a later workup the sera was nonreactive at 4C and RT, so doesn't this mean that this is not a cold agglutinin? You mentioned that in an earlier workup it looked as if a cold agglutinin might be developing. What is the explanation for the nonreactivity with enzyme-treated cells? Is this an antibody to a HFA or a HTLA that is denatured by enzymes? In the aforementioned article, in the flowchart presented on page 1541, there is a step where the autocontrol is negative or weaker than the reaction with panel cells, there is persistence of panagglutination after auto- and alloadsorption, there is no reactivity after papain treatement, and the flow leads one to think maybe there is an anti-HFA or anti-CH/RG..... Why are the PEG/IgG crossmatches all compatible, and are they incompatible without the PEG? I would like to understand this situation better, and hope you don't mind my questions... Thank you!

[b I was going to ask you what a BLOOS film is.!!!!!:D:D:D;) I've posted a couple of misspellings myself Malcolm. It is always horrifying to me to go back to one my posts and find a misspelling. I guess it proves that we are all human. Although, I will admit it is refreshing to see that even you are!!:D:D:D:D:D:D