Tympanista

Do you report a titer for the thermal amplitude or just the temperature of reactivity?

The technical manual says to prepare the serial dilutions up to 1:4096. Does anyone take their dilutions out further? Our LIS is currently set up to report up to > 8192, but is there really any clinical significance to reporting a value greater than 4096?

My goal is to convince the physician that the thermal amplitude is the appropriate test for these patients, but some physicians are resistant to change, even when presented with definitive evidence to the contrary.

Thank you for the references. I'm always curious to know what is being done in other labs. We don't currently perform thermal amplitude testing here, so that may end up being a sendout test. I've been tracking all of the cold agglutinin titer orders we've gotten over the past few months and they all seem to be coming from one physician who is ordering them as part of an autoimmune panel for patients with Raynaud's. I will have my Medical Director speak with him after reviewing the reference you provided and we may be able to convince the physician to request thermal amplitude testing along with, or instead of the cold agglutinin titers.

My facility purchased a Helmer UltraCW II cellwasher last summer (prior to my employment here) and I have been told they had a very difficult time during the validation process when trying to produce a clearly delineated cell button during the spin phase. They supposedly contacted Helmer and were told that this particular model does not produce a "good" cell button. I have been trying, unsuccessfully, to perform the annual calibration and no matter how long I spin the tubes I cannot produce a clearly delineated cell button in the negative tubes. Has anyone else had this issue?

I will check to see if that is causing the problem. Thank you for the suggestion.

SMILLER: Thanks for your response. I only spun the tubes for 2 minutes to see if the cell button in the negative tubes would be more clearly delineated than it was at 20 and 25 seconds. Our spin times are set at 20 and 25 seconds, depending on which centrifuge we're using. We have 2 cellwashers and a regular centrifuge that we use in our Blood Bank, and none of them are giving us a good cell button with the negative tubes. I'll have to follow up with our Clinical Engineering staff to find out how often they check the RPMs.

I am revising a 30 year old procedure for centrifuge calibration based on the procedure in the Technical Manual. When you check the tubes to see if "the cell button is clearly delineated and the periphery is sharply defined, not fuzzy" is this for the positive tubes only? I have tried the immediate spin procedure taking the centrifuge time all the way up to 2 minutes and the cell button is still not clearly delineated for the negative tubes. I reviewed the calibration records from the past few years and they have been choosing a centrifuge time of 20 seconds based on the fact that the cell button was not clearly delineated in the negative tubes at 10 and 15 seconds, but it supposedly was at 20 seconds. I really don't believe it has ever been clearly delineated at 20 seconds. That was just the suggested time from the manufacturer, so I think they have been "making it work" each time a calibration was done. Should the cell button be clearly delineated for the negative tubes or should we only be looking for a defined cell button in the positive tubes? My centrifuges meet all of the other criteria in the Technical Manual (clear supernatant, cell button easily re-suspended, etc.) using only a 10 second spin, so I was just curious about how other facilities interpret the procedure.

I agree, Malcolm, I believe the titer is not clinically significant, but I haven't yet convinced the ordering physicians of this. I will save the reference you cited in case I have an opportunity to plead my case. We don't currently perform thermal amplitude testing at my facility, so we would have to send the specimens to a reference lab if we decide to do them. Thank you for your input.

Would anyone be willing to share their cold agglutinin titer procedure with me? I am a relatively new Blood Bank supervisor and, though I have many years of Blood Bank experience, I have no reference lab experience. The procedure at my new facility hasn't been revised since 1999 and has several glaring issues. For example, it says to incubate the tubes "overnight." Is that for 8 hours, 24 hours? I reviewed the procedure in the Technical Manual and it makes much more sense to me, but I was hoping I could get some examples of what is being done at other facilities. I would appreciate any information you all are willing to share. Thanks.

Both patients have afibrinogenemia. I am also curious as to why they are still receiving cryo, as opposed to a fibrinogen concentrate, but my pathologist is not very experienced when it comes to transfusion practices.

We spike a bag of saline to add to the pooling bag. I would love to switch to pre-pooled cryo, but our supplier only offers 5-pools, and the physician caring for our regular cryo patients insists on 6, 12, or 36 units, depending on the patient. : (

Is it standard procedure to add a small volume of saline when pooling cryo in order to aid with resuspension of the precipitate? At my previous job we did not add saline, but I just began working at a different hospital and their procedure calls for the addition of approx. 30mL of saline to the first bag. I'm not against the addition of the saline, but we have several patients who receive routine transfusions of cryo (up to 36 units at a time). Adding saline to the first bag and then using the contents of each subsequent bag to resuspend the next bag is very time consuming. The procedure at my previous employer was to just spike into each bag and drain as much of the contents into the transfer bag as possible. This was much less time consuming. Is the recovery of the precipitate significantly increased by the addition of saline and subsequent resuspension of each bag with the previous bag's contents (i.e. enough to justify the added time involved)? I'm just curious to hear what other facilities are doing.