Automated Solid Phase vs Manual Solid Phase

[Even0404]

Hi Everyone,

 

I am new to this site, but could not find any threads specifically pertaining to some of the peculiar solid phase issues my lab seems to deal with. We have one Echo, one Galileo, and a solid phase station. We have been using them for a number of years. Like many people have posted on the forum, there seems to be some strong panagglutiniation “false positives” but ours only appear on the machines. 

 

Interestingly, if we run these samples in manual solid phase (MSP), both the screens and panel cells will be negative (or show an underlying antibody). Warm autos are then ruled out. If it is still a panagglutinin in MSP, we move to gel and follow through with warm auto testing. Though MSP is supposed to be a little less sensitive than the machines, a 3+ does would not normally turn negative.

 

I am posting to see if anyone has the same experience, where machine solid phase testing is all positive and manual solid phase testing is negative. This leads me to believe that the “solid phase antibody is actually an antibody to the pre-embedded screen and panel strips because there is no other difference between the two testing methods.

 

Does any one else go to manual solid phase before going to their secondary method?

[Even0404]

I should clarify that when we go to manual solid phase screening, we do not use the pre-embedded strips. We test with select strips that we embed with immucor bottled screening cells.

 

Also, some lots do this much more than others but we rarely go a whole lot without this situation coming up a few times.

[AMcCord]

I don't use manual solid phase to check up on funky results with automated testing - we've been using PeG/tube. However, recently I've done a lot of reading about solid phase testing and I've talked to some people about those sorts of results. There are some who feel that the 'reactions' we are seeing with the pre-embedded strips may represent antibodies directed against parts of the red cell membrane that are not normally exposed. Once the membrane is disrupted to 'paste' it in the well, these sites are exposed. Some other type of non-specific reactivity related to the way the cells are treated during manufacturing could also be part of the explanation. The liquid cells you are using with the Select strips don't have that issue, so it doesn't surprise me that you are getting negative results.

 

Some reactivity with the ReadyScreen 3 and Ready Extend strips could actually be newly forming antibodies. There were some interesting posters at AABB in Denver that looked at that. That said, what you see going on sounds like it's related to the manufacturing issues Immucor has been having lately. They say they have made some changes in the manufacturing process and have started producing product again. Hopefully the 'new' strips will reduce the problems (and frustration) we've all been experiencing.