Hello.  Does anyone ever use a 4:1 (serum to cells) ratio when investigating antibody IDs?  If so, do you use enhancement and/or have an SOP? Just looking for documentation to confirm it as a valid procedure.  Thank you.

Only when using standard laboratory saline to suspend the red cells, and yes, we have an SOP for this (as for ALL techniques we use).  If we are using LISS, however, it is vital that a 1 to 1 ratio of serum/plasma to red cells is used, to prevent either false positive or false negative reactions, as anything else would change the overall ionic strength of the reactants in the test.

The package inserts for your enhancement medium will tell you if it is acceptable to use more plasma/serum. As Malcolm says, no for LISS.

Do you have references for your SOP?

Unfortunately, I no longer work for NHSBT and so I no longer have access to the SOP.

One of the classic ways of increasing sensitivity is to increase the serum:cell ratio.  Used to do that a long time ago.  I've never done that with enhancement media.  I don't know if they still do but I believe Canada used to use 10 drops of serum/drop of cell suspension.

21 hours ago, Okie said:

Hello.  Does anyone ever use a 4:1 (serum to cells) ratio when investigating antibody IDs?  If so, do you use enhancement and/or have an SOP? Just looking for documentation to confirm it as a valid procedure.  Thank you.

Not for atypical allo-antibody IDs.

Scott

Why not Scott?  It was standard practice back in the day, and we didn't kill too many people, even then!

20 minutes ago, Malcolm Needs said:

Why not Scott?  It was standard practice back in the day, and we didn't kill too many people, even then!

That's the truth.