AB Positive Control

[Brenda K Hutson]

Question for all of you: If you run a control for group AB Positive, are you running it:

1. On initial specimen only?

2. With every specimen?

3. Any time you have to pull that specimen out and perform a blood type (i.e. perhaps a confirmation of

forward type only if Type and Screen done but additional RBCs ordered at a later time)?

And am I missing something because I do not even see a reference to this in the Technical Manual??

Thanks,

Brenda Hutson, CLS(ASCP)SBB

[Malcolm Needs ☆]

We perform a long group (and a confirmatory group) on all samples once. The long group contains a negative control.

[velliott]

Same as Malcom....there isn't a place to record additional controls...only on the original specimen.

[David Saikin]

What control are you talking about? A cell control (Rh) because the pt is AB+ or an auto control with the antibody screen? We run Rh ct with AB+ pts x1 just to make certain of the blood groupings. After the initial typing we are not concerned.

[tbostock]

We just run the Rh control once, on the first specimen, since all other cells for the forward typing are positive. Once the patient has AB Pos in their history we don't do it again. The computer is set up to "require" the Rh control for AB Positive, so if the tech does not perform it, they put in an exception code of "previously typed as AB Pos".

[Irene59]

Any time the patient has an ABO/Rh ordered, regardless of HX, we do the control. In our computer system, Meditech, there is a line to record the control.

[adiescast]

We run the control for the first type on each AB+ sample. After that we run only the forward type if we have to pull the sample again during its 3 day dating.

The Technical Manual refers to this process obliquely in the Method 2-13 under Interpretation. The Procedure states to run a control with the D testing. The Interpretation (step 3) states that a negative test with anti-A or anti-B is a valid control. This implies that you do not have to run a negative control if your anti-A or anti-B is negative, but you do have to run a control if they are both positive.

[pdameron]

The requirement comes from the anti-D package insert. We test a control each time for AB+ patients or the computer will not recognize the reaction pattern as valid.

[John C. Staley]

In my previous life we did the control for AB+ patients on two samples, if confirmed we never did it again on that patient. The second sample was NEVER drawn specifically for this testing, it was just the second time we happened to be testing this patient be it 3 days or 3 years from the first. We had a similar procedure for wD testing as well.

:faint:

[Brenda K Hutson]

What control are you talking about? A cell control (Rh) because the pt is AB+ or an auto control with the antibody screen? We run Rh ct with AB+ pts x1 just to make certain of the blood groupings. After the initial typing we are not concerned.

Yes, I am referring to the AB POS Control.

Thanks,

Brenda

[Brenda K Hutson]

We just run the Rh control once, on the first specimen, since all other cells for the forward typing are positive. Once the patient has AB Pos in their history we don't do it again. The computer is set up to "require" the Rh control for AB Positive, so if the tech does not perform it, they put in an exception code of "previously typed as AB Pos".

Ah...

Our computer is not set up to require it (I think it would have to be an all or nothing field). We have to unmask the field to put in a reaction. I "wish" our Truth Table would warn staff when they don't perform the control (though I guess you would then run into the issue of either having to perform the control everytime you get specimens on the AB POS patient vs. only once; or you would have to override the warning after you test it initially). Just out of curiousity then; do you perform it with every specimen since the computer requires it? Or, do you actually have a computer system that can tell whether it is the first typing on a given patient, and not require it after that (not sure such a system would/could exist).

Brenda

[Brenda K Hutson]

We just run the Rh control once, on the first specimen, since all other cells for the forward typing are positive. Once the patient has AB Pos in their history we don't do it again. The computer is set up to "require" the Rh control for AB Positive, so if the tech does not perform it, they put in an exception code of "previously typed as AB Pos".

Should have read your response more thoroughly before responding! I see your explanation of what your computer does.

Thanks,

Brenda

[Brenda K Hutson]

We run the control for the first type on each AB+ sample. After that we run only the forward type if we have to pull the sample again during its 3 day dating.

The Technical Manual refers to this process obliquely in the Method 2-13 under Interpretation. The Procedure states to run a control with the D testing. The Interpretation (step 3) states that a negative test with anti-A or anti-B is a valid control. This implies that you do not have to run a negative control if your anti-A or anti-B is negative, but you do have to run a control if they are both positive.

I could have sworn that when this requirement first came out a number of years ago, it was spelled out more thoroughly.

Brenda

[Brenda K Hutson]

The requirement comes from the anti-D package insert. We test a control each time for AB+ patients or the computer will not recognize the reaction pattern as valid.

Actually, the way the Anti-D Insert reads (at least ours) is that if it is reactive with Anti-A, Anti-B, Anti-D and the DAT is Positive, then run a D Control.......

We do not routinely run a DAT so that statement can be a little misleading to someone who is not aware of the D Control issue with AB Positive Types.

Brenda

[rravkin@aol.com]

We run an Rh Neg control once for each indated specimen to rule out panagglutination.

[Brenda K Hutson]

We run an Rh Neg control once for each indated specimen to rule out panagglutination.

With regard to your "reasoning" for running it with each specimen, just my thoughts....

Isn't the purpose of doing it (as established some years ago), really to ensure your patient is AB POS (and that they do not erroneously appear to be that type because of panagglutination)? After the first time, seems the purpose changes to looking for panagglutination (by your Policy) vs. ensuring the accurate blood type of your patient....

I'm not saying you are wrong; just "food for thought."

Thanks,

Brenda

[rravkin@aol.com]

With regard to your "reasoning" for running it with each specimen, just my thoughts....

Isn't the purpose of doing it (as established some years ago), really to ensure your patient is AB POS (and that they do not erroneously appear to be that type because of panagglutination)? After the first time, seems the purpose changes to looking for panagglutination (by your Policy) vs. ensuring the accurate blood type of your patient....

I'm not saying you are wrong; just "food for thought."

Thanks,

Brenda

Hey Brenda,

You are exactly right. I don't understand why the continuence of an Rh-Neg control with a historic AB Pos other than, as you say, to rule out panagglutination. Maybe you can give some insight on the relevance of panagglutination outside of the obvious distortion of the ABO/Rh type.:)

[Brenda K Hutson]

Hey Brenda,

You are exactly right. I don't understand why the continuence of an Rh-Neg control with a historic AB Pos other than, as you say, to rule out panagglutination. Maybe you can give some insight on the relevance of panagglutination outside of the obvious distortion of the ABO/Rh type.:)

Well, I guess the best thing would say is "don't go looking for trouble!" Ha Ha It is along the lines of:

1. Automatically running an autocontrol with all of your Antibody Screens

2. Looking at all reactions under a microscope (as has been the history of the staff where I have been for a few

years now; even ABO Typing. I say, if you don't want to create your own problems then don't go looking for them.

Brenda