PeterD

The fact that a second spinning of a gel card can create a negative impression in a gel column of a weak reaction should not suprise any experienced immuno hematologist. The practice of placing any credibility in a result after a second spin seems reminiscent of technologists who using tube testing would shake a weak reaction away. I whole heartedly agree with those who are advising to follow the manufacturers guidelines and interpret reactivity after a SINGLE spin only. Weak reactivity of an antibody with low avidity can easily be dispersed. I would guess this is what is occurring after a second spin. Weak reactivity and low avidity do not always translate to clinically insignificant. Having observed the phenomenon described (i. e. weak reactivity becoming negative) many times when using a gel card on subsequent patients would lead me to believe this can occur easily. Furthermore, it should not be interpretted as a negative result nor should not be considered clinically insignificant until an appropriate workup is performed.

Thanks for the responses, as they gave me something new to anticipate. The cases that we have seen already have been problems with the reverse grouping having unexpected reactivity that made them discrepant with the forward grouping. Additionally, when performing tube testing, the discrepancies were not present. My feeling about these cases would be to use the tube testing results and call it a day. In one of the cases the patient had been typed by tube only several weeks before without problems. I tend to think that performing a complete workup to identify a cold auto antibody at reduced temperatures and cold auto adsorbtions to get the reverse group to agree with the forward group in gel is overkill. That is what we have been doing and I was hoping someone would validate my sense that this amount of work is not necessary. I would still be interested to hear from those who agree or disagree with my method of resolution as I am guessing we will be making some policies regarding this matter and I would like to present some details of how different institutions are proceeding in these cases. Thanks again, Peter

I am interested to hear how institutions that use gel card testing for ABO and Rh testing deal with the apparent higher frequency of ABO forward and reverse grouping discrepancies encountered with this technology . The transfusion service in which I work has just begun using gel cards to perform typing and we have already had several of these occurences that were not reproducible in tube ABO testing. (We have been using gel for antibody screen and antibody ID for 12-15 years) At present, these situations have led to extensive antibody workups to identify nothing more than cold auto agglutinins in the patient's serum. These workups also included cold auto adsorbtions. I have a sense that this extent of workup is not necessary, and wonder what other places are doing for resolution. Keep in mind that I am not talking about cold ALLO antibodies but cold AUTO antibodies that would not have been detected using ABO tube testing. Thanks in advance for your advice.

In response to Lara's question I have a question that is still unclear to me. From what is written it sounds like you are screening in gel and trying to identify specificity using a different method, (i.e. tube methodology). If this is a correct assumption on my part then the explanation to no reactivity in the panels is that you are using a less sensitive method. If you are using gel panels then the explanation is less obvious. In my institution, we run all panels in the same method that we detect reactivity. This is because we frequently encountered weakly positive screens in which we could not identify specificity when using tube panels. If you cannot run gel panels, I would suggest testing your panels in PEG which will often give you comparable results to gel.

I am glad to hear that some others find this subject a source of frustration and that some others have questions as to the effectiveness of it all. I too see compliance as a difficulty. In my situation, I am surprised at the lack of preparation of our staff in terms of basic information about the program. I think if we had a greater sense of our own security that may be at stake, the specific reasons it is being imposed, and how our personal information will be used and protected, we may feel more at ease with the process. Instead the whole thing is shrouded in mystery. I fail to understand why some basic specifics of the program in written form could not have been provided. We have not been able to ask any questions and receive any information other than shear logistics of getting it done. Since it seems to be an important issue to the NRC one would think that they would like to get everyone it effects on board from the front. It would be great to have somebody in authority available to answer basic questions that come up. However it also appears that that is not part of the plan maybe even by design. Thanks all for your thoughts and information.

Thanks dmpollock for your response. I had found the above information online shortly after posting my question. It would seem that compliance is compulsory as long as the institution maintains a CsCl source irradiator. Since increased security is obviously the objective, my question still remains how precisely does fingerprinting of people with routine access achieve this goal. I would assume background checking is part of this process, but what other purposes does it provide, if any? The requirement is clear, the practice is less so. Interesting times we live in. Thanks again.

We have just been informed in our blood bank that we need to head to the local police department to be fingerprinted due to security issues involving Cesium irradiators. The manager was not very forthcoming with details yet but insinuated it was a homeland security issue. When questioned if it were required to maintain employment, the answer was yes. Does anyone have experience with this issue, who is requiring it, what if any options are open to blood bankers, and what other legal issues are involved. I am reluctant to submit to allowing this and other personal information to be placed into any sort of database, no matter who is making the request. Are there any choices in this matter and where can reliable information be obtained to what purpose this will serve?