Does anyone have any suggestions on how to make up an elution unknown? I have people who need practice working up an elution, our CAP sample isn't scheduled until March and there usually isn't enough to pass around.

Well, the antibody doesn't have to be rare, so why not just use some D+ red cells and some anti-D?.........or isn't that what you mean?

That's what I do as well for my students and trainees. That's easiest, but you could also use any outdated IgG antiserum or nice patient IgG antibody. Mix 1 cc serum and 1 cc antigen-positive packed cells, incubate 30 min at 37, check to make sure it's DAT-positive and away you go.

You can make a quick recipe of 3-4 pigtails from an O Pos donor plus 10 drops Check Cells. You might have to adjust a bit depending on the size/red cell volume of the pigtails, but this makes a nice weaker DAT sample that works well.

Thanks AMcCord that sound easy enough I think I will use it.

Similar to how Dr. Pepper described, you can also make up a patient sample to mimic a warm autoantibody by added several drops of Anti-e to e pos red cells, incubating, then washing, etc.

For the patient's plasma, you can either use plasma that contains no unexpected antibodies, or you could add a couple drops of the Anti-e if you want the specimen to have the autoantibody in the plasma in addition to on the red blood cells.

This is so awesome that this was up for discussion today! I was just looking for a recipe for creating a positive DAT. I was going to do what Malcolm suggested. Do I have to incubate that or just combine and give to the student to test?

You have to incubate, otherwise the IgG antibody will not sensitise the red cells quickly enough.

One thing about using reagent anti-D: most are mixes of monoclonal IgM and IgG, to react in rapid tests and weak D tests respectively. The elution procedure should work fine, but you may find the cells agglutinating spontaneously in a DAT test due to the IgM component in the reagent. Our DAT procedure is, if positive with polyspecific AHG, to repeat with anti-IgG, anti-C3 and saline as a negative control. The saline control can come out positive with cells prepared this way.

Thanks Phil. I'll remember that and do the testing before I give to the student to test.

I agree Phil. I was thinking about using a genuine patient's anti-D, which should be reasonably easy to come across. Of course, it doesn't need to be an anti-D. Any specificity made by a patient would do, providing that red cells expressing the corresponding antigen are available.

Yes. Agree. I have seen the same. But I tell my student to perform only DAT IgG once I knew this was happening. (I know cheating but they are learning elution)

One thing about using reagent anti-D: most are mixes of monoclonal IgM and IgG, to react in rapid tests and weak D tests respectively. The elution procedure should work fine, but you may find the cells agglutinating spontaneously in a DAT test due to the IgM component in the reagent. Our DAT procedure is, if positive with polyspecific AHG, to repeat with anti-IgG, anti-C3 and saline as a negative control. The saline control can come out positive with cells prepared this way.

For the patient's plasma, you can either use plasma that contains no unexpected antibodies, or you could add a couple drops of the Anti-e if you want the specimen to have the autoantibody in the plasma in addition to on the red blood cells.

This one works very well.