Daily Reagent QC, what are you doing?

[Dawn]

We would love to know what everyone is doing for daily reagent QC. In addition to responding to the polls, respond to this post with details. Are you using a commercial kit? Do you make your own QC reagents? Do you have an interesting way to handle QC?

[Jane]

We use our reagents to QC other reagents. For example- to QC the anti-A we use the A cells and the B cells. This has worked well for us for years and keeps us from needing to buy any QC kits.

To QC our screening cells (in gel) we use expired antisera- usually duffy or kidd. We dilute with albumin to the 1-3+ required by CAP and freeze aliquots. These will stay reactive for a long time and again help us keep costs down.

[Cliff]

What do others think about using only positive controls? Most of our manufacturers only require a positive control. Currently we perform both positive and negative controls, just as described by Jane.

Personally I am opposed to only doing positive controls, but unless I have evidence that it's wrong I will be outvoted. I think using a positive control only method is about as valid as not performing QC at all.

[adiescast]

We also use our reagents to QC our other reagents. We do antisera A and B against our reverse cells and A,B against our A2 cells. We do anti-D against positive and negative screening cells. We do our check cells against saline and AHG. We do our complement AHG against complement check cells. These are all done by lot number rather than by vial or rack. For the screening cells, we make up an antibody reagent that will react 1-3+ with all three cells in the set (anti-D and anti-c). We test the screening cells with the LISS and AHG reagent by rack to ensure activity in each vial of AHG.

For solid phase, there is a positive and negative control for each run. Positive (heterozygous) and negative controls from panel cells are done with each (non-ABO) antisera each day of use.

As far as using only positive controls for QC: I think the philosophy behind that is that you will get plenty of negatives in your run to show the negative reaction, but you might not get a positive, so you need to show that the reagent will react appropriately with the positive if there was one present. I would think that the only time that would be a problem is when you are testing something that shows positive for most runs (Like a cellano antigen). In that case, you might want to show that your positive is not false by running a negative control. Just my two cents...

[Cliff]

For those following this thread, part of the reason we are changing our practice is this requirement from JCAHO to QC each open vial, this is the 2004 edition, I don't 2005 handy, but I don't think it's changed:

Standard QC.5.220The laboratory tests for reactivity the potency and reliability of reagents used for ABO grouping, Rh typing, antibody detection, and compatibility determinations on each day of use and when a new lot of reagents is first used.

Elements of Performance for QC.5.220

• Each opened vial of antisera, reactive cells, and reagents is tested for reactivity on each day of use and when a new lot of reagents is first used.
• The laboratory confirms that each reagent reacts as expected.
• Results are documented.

[schorj]

For our screening cell QC, we purchase a liquid plasma from our blood center that has a known weak (1+ or 2+) anti-D antibody. We divide the plasma into 25 ml aliquots and freeze the aliquots, thawing each aliquot as needed. This meets our QC needs for at least two months. The price of rare antisera is just too high to use these reagents for QC, even if it is outdated.

We just use a two cell screen, so anti-D works. If you use a three cell screen, I'll bet your blood center may have a donor, on file, who has the right combination of antibodies to give you positive reactions in all three cells. The blood centers don't have much use for this plasma, that contain allo-antibodies, so they will be happy to sell it to you.

[Kochman]

I'm surprised to hear people indicating that their reagent manufacturers' package inserts do not include directions to use both a positive and a negative control, unless these are for reagents that are not U.S. licensed. During the review and aproval of U.S. licensed reagents, the QC directions are reviewed to ensure that they require use of appropriate positive and negative controls.

If anyone knows of a an example where this is not the case, we sure would like to hear about it. kochman@cber.fda.gov

[sgoertzen]

We use the Immucor "CorQC" kit. We QC each reagent vial used each morning and whenever opening a vial with a new lot number.

[caj1018]

We use purchased QC reagents and test each reagent daily following the manufacturer's directions. In addition, we perform a negative control of our MTS Gel cards using the MTS diluent. Having been burned once many years ago this simple step prevents a major headache.