saline replacement in serum discrepancy

[Brenda K Hutson]

Well, just because your Antibody Screen is negative in tube and GEL, that does not necessarily eliminate an Anti-M (or any other cold reacting antibodies; i.e. P1, Lea, Leb, etc). They may be reacting only at colder temps.; just enough to cause you a little grief in trying to figure it out.

Brenda

Hi Brenda,what a big help!thats the advantage of being a member of this forum,I do appreciate to all the people who had shared and answered to my thread,thanks blood bank talk:)...P.S. anti-M is eliminated, because antibody screening is clear negative both in tube and gel method.

[Brenda K Hutson]

Well, I could see a negative control with an O Cell to perhaps assist with the question of whether the problem is an Anti-A1. But as far as rouleaux or reactivity due to a cold agglutinin, I am not seeing how this O Cell Negative Control is going to be of assitance to you?? Perhaps I am just missing something??

So my own personal approach would be:

1. Depending on the strength (and perhaps what the GEL Screen looks like in that Rouleaux and Cold Agglutinins can have a

different look), I would most likely check for rouleaux first (easiest thing to do).

2. If patient group AB, would definitely type with A1 lectin.

3. If patient goup A, would still probably type with A1 lectin; but not sure "at what point." Sometimes things are just "case by

case."

4. So I might then be interested in the Cold Panel (which will use the 3 Screening Cells so I can also see if I have a cold with

a specificity which might be interferring with my reverse type. If yes (i.e. anti-M), you need to find A1 cells which are M-

to retest (i.e. you could screen some of your group A units with anti-M). Just a thought...

5. And if it is a really strong cold agglutinin, you may be able to see it (if you use EDTA specimens) by tilting the tube onto its

side and seeing whether the RBCs flow freely; or whether it appears to be a clump.

Brenda Hutson, CLS(ASCP)SBB

yes ,khalidm3 i agree that we need to have negative control in reverse by using o cells.

[profbaud]

If the rouleaux is identified by the appearance of "stacked coins" under the microscope then I tell my staff that to see the dispersal of this formation, it is necessary to look under the microscope after the replacement of plasma with equal volumes of saline.

[GilTphoto]

I had a tech who constantly reported rouleaux when in fact it was a weak cold agglutinin.

You must NEVER do Saline Replacement after Immediate spin phase. First incubate the antibody screen or crossmatch at 37C, if it goes away, it was a cold. If still there, then do Saline Replacement.

[Brenda K Hutson]

Never heard that one....

If I get an ABO Discrepancy and see "stacked coins" under the microscope on an unexpected positive reverse typing cell, I am going to do Saline Replacement. If I do an Immediate Spin Crossmatch; it looks rough and upon looking under the microscope I see stacked coins, I am going to do saline replacement.

A cold should not be displaced by Saline Replacement (so maybe the issue was more one of your Tech., in addition to not really knowing what rouleaux looked like, not properly performing a saline replacement).

I look to my Antibody Screen to pick up any "clinically significant" antibodies; including at times the nuisance cold agglutinin that "most of the time" is not clinically significant anyway.

Brenda Hutson, CLS(ASCP)SBB

I had a tech who constantly reported rouleaux when in fact it was a weak cold agglutinin.

You must NEVER do Saline Replacement after Immediate spin phase. First incubate the antibody screen or crossmatch at 37C, if it goes away, it was a cold. If still there, then do Saline Replacement.