red cell button sticking to tube

[KPayne]

We are observing that red cell button seems to stick to 12x75 tube when reading reaction with A and B antisera. Have looked at tubes,centrifugation, saline, individual techs, mixing of EDTA sample - would appreciate any suggestions to remedy this problem.

[Lcsmrz]

We've never had a similar problem using glass 12x75 tubes. Plastic tubes are a different story.

[David Saikin]

well said Larry . . . I tried plastic tubes but did not really like some of the reactions, particularly with the Immucor rosette test.

[GilTphoto]

We have had a similar problem with shaking off Anti-A. I think it's too long a spin time. Our current spin time is 20 seconds as determined by the centrifuge calibration procedure done once a year. I think it should only be 15 seconds (which is the default for the immunofuge), but what do you do if the calibration procedure tells you otherwise?

I told the tech who performs the calibration procedure to find a way to show that 15 seconds works, but the procedure of diluting the antibody used for testing is not real life situations. We have been using patient samples for the anti-A or anti-B, since diluting the monoclonal reagents requires a 512 or 1024 dilution to get that 1+ reaction the calibration procedure wants. She always gets 20 seconds as the ideal spin time!!

[Malcolm Needs ☆]

I am no expert in this, but I understand it is something to do with the static electricity that you get with plastic tubes that you do not get with glass tubes. As I say, I am no expert, and so this could be apocryphal.

[BankerGirl]

We use glass tubes and have noticed this with only anti-D when we perform our daily QC. All other reagents seem to be fine. If anyone gets the answer, let me know. We also spin for 20 sec.