Carry Over on ProVue

[eeagan]

We have just resolved a problem with carry over on the ProVue and I'd like to know if anyone else has experienced the same thing. The carry over was only seen on the antibody screen and with strongly positive specimens. We were fortunate in that 2 of the specimens involved were prenatal specimens. So titers were done on them. One specimen had anti-c (128), anti-E (128) and anti-K (8). Carry over was seen with the anti-c and anti-E but not with anti-K. The other specimen had anti-D (128) and anti-C (2). Carry over was seen with anti-D on both Rh positive cells. The last specimen contained anti-D, titer unknown and carry over was seen on both Rh positive cells.

The problem turned out to be caused by a reversal of the tubing of the wash solutions. At some point in the system, the tubing for solution A was connected to the hook up for solution B and vise versa. This was not the connection at the wash bottle but further back in the system and was done by the Ortho repair tech. While it seems likely that the problem occurred because of an error on the part of the repair tech, I'd like to know if anyone else ever encountered carry over on the ProVue.

[Liz]

Does the company realise that his mistake could have cost the life of a patient if it had mixed up blood groups and others?

[eeagan]

I don't know if Ortho has said so in words, but I'm sure that they realize the implications. I've yet to do a detailed search of patient results, but so far I am not aware of any false negatives due to the carry over. We're only aware of false positives which caused extra testing and some delay of completing crossmatches.

[eeagan]

I would like to add that we did not see any carry over in the ABO/Rh typing.

[Malcolm Needs ☆]

I would like to add that we did not see any carry over in the ABO/Rh typing.

There may be three reasons for this.

Firstly, most commercial reverse grouping cells are rr (and often pools) and secondly, these tests are incubated at RT, whereas your screen is incubated at 37oC, and, of course, your ABO/Rh typing does not involve AHG, whereas your screen does.

It could be one, two or all three of these reasons.

;);)

[eeagan]

Everything that Malcom wrote is true for explaining why no carry over was seen in the reverse typings. As an interesting note though, the first specimen that made the staff realize that there was possibly carry over contamination had a back type discrepancy due to anti-c. Her anti-c was capable of reacting with the Rh negative c positive A1 cells. This happened on the ProVue and in manual tube testing. There wasn't extra reactivity in the back type with the specimens that did have carry over in the antibody screen.

I'd still like to know if anyone else experienced this problem.