We’ve recently noticed that our two different lot numbers of Bioclone anti-D have been giving us a 2+ reaction with the Ortho Confidence System when we spin immediately after we add the positive QC cells with the antisera. The reaction strength is stronger if we let the cell/anti-D mixture aside for 30 - 60 seconds and then spun. I was told by Ortho that the D expression on some of their QC cells may be weaker some times thus the 2+ reaction. The QC package insert only states that a positive reaction is expected, but it doesn’t state what strength to expect. Has anyone else seen this?

Yes, we have noticed this, too, the reactions are a little weaker that what we've experienced in the past. But since we've switched to gel if we need to perform a tube typing that testing is (eventually) recehecked with gel technique.

Randy