Mixed Field Testing Interpretation

[jason009]

Hi all,

I just want to know what other facilities do for a patient that have mixed field results on the front type in gel testing, but have a straight forward type in tube testing when the patient has no history.  I cannot find much literature on this.  If a patient has a history that matches the tube type then obviously, we would follow the tube type for resulting.  If there is no history to be found would you give the patient O RBCs?  The example that stirred this post was a patient that recieved 2 Opos and 2 Apos units the day before they came to our facility and in gel there was a mixed front type between O and AB.

Thanks everyone.

Jason

[Ensis01]

ABO mixed field must be explained; find out patient transfusion history. If it is not clear what their blood type is, or if the mixed field cannot be explained (patient intubated, confused etc.) document and give type O.

Interpretation of mixed field in gel is easy, harder in tube but I would expect it to be there. I would therefore suggest checking very carefully for mixed field by tube (this may be an occasion to use a microscope to confirm mixed field if needed). Sounds like this is a good sample to use for mixed field training in your lab.   

[AuntiS]

I agree with Ensis01.  

Sometimes gel can give a false positive - if there is a problem with the card/well or sample (bit of fibrin, etc) - which is resolved upon repeat and/or tube testing.

Otherwise, yeah, if you can explain it = great, group specific (meeting all other policy, of course)  If not = O.

sandra