Dear friends

when we should use albunim 6% as a control, and albumin 22% as control, and why?

I use 6-8% albumin for my Rh control; theoretically you only need to run it when the pt types as AB+. I would never use 22% alb as a control (unless using a high protein anti-D: has there been one available in the past 20 yrs?).

You need to use a control that is equivalent to the reagents you are controlling. Most of the time, companies sell a reagent control. This is actually NOT a waste of money. The reagents contain lots of things in their buffers in addition to albumin and you can occasionally get patients who react with these other things too, giving you a false positive result

We use 7% Albumin as control in patients that type ABpos (rule out polyagglutination).

We are implementing gel blood type testing at one of our hospitals and I am running into all sorts of opinions of how to make up 6% albumin to use as a negative control for the reverse typing test.  We don't think they will be able to come by AB plasma consistently so we are looking at other options. What are others doing?  Do you use 22% bovine albumin and dilute with saline, or MTS diluent 2 or MTS Diluent 2 Plus?  Or do you use 25% human albumin and dilute with saline or...?

22% diluted to 6% with saline

 

We are implementing gel blood type testing at one of our hospitals and I am running into all sorts of opinions of how to make up 6% albumin to use as a negative control for the reverse typing test.  We don't think they will be able to come by AB plasma consistently so we are looking at other options. What are others doing?  Do you use 22% bovine albumin and dilute with saline, or MTS diluent 2 or MTS Diluent 2 Plus?  Or do you use 25% human albumin and dilute with saline or...?

 

I use the cell diluent as my negative control for both the back type and IgG cards; if positive then either my cells or my diluent are contaminated (unless the card itself is funky). If you want to use albumin, the easiest way is to dilute 22% albumin 2:1 with blood bank saline. This comes out to a tad more than 7% but I think that is reasonable AND EASY to do.

What cells are you using for your reverse?  You could just juse a group A as a neg control for the A cells and B for the B cells.......

We will use Ortho's pre-diluted 0.8% reverse cells--Affirmagen. These small hospitals may not have a B patient in any given week.  Using plasma seems to me like a better negative control but if using it makes the process of running QC really complicated and 6% albumin (or even the empty diluent --is that diluent 2 or 2 Plus, David?) will work adequately then I would consider it.  I would like to have an adequate, cheap, simple negative control. 

 

Aren't both diluents LISS?  Does that alter the reverse type to have it in both the reverse cells and the diluted albumin used as a negative plasma sample?

I use Gel Cell Diluent from Hemobioscience - it is the equivalent of MTS2+. I would use saline to dilute the albumin, not the cell diluent.

Forgive me for being so dense, but why do you need a negative plasma control when doing ABO reverse grouping in Gel?  Are you trying to demonstrate that the AFFIRMAGEN cells do not spontaneously agglutinate in the presence patient plasma?  or Do you want do demonstrate that the AFFIRMAGEN cells do not spontaneously agglutinate in the Buffered Gel?  I assume you are using and A/B/D Monoclonal and Reverse Grouping card.

 

If appropriate patient plasma is not available, I would just add the AFFIRMAGEN cells to the Buffered Gel columns, centrifuge and read.  There is your negative control. 

Edited May 2, 201411 yr by Dansket

From what I can gather, Ortho recommends using AB plasma or 6% albumin as a negative control.  Otherwise, I agree with you, Dansket.  6% albumin mimics the protein content of plasma but that is about it. I guess using it is looking for whether the Affirmagen cells will spontaneously agglutinate in a mileau that has the same protein content as plasma?  Maybe it just makes everyone feel better.

Mabel,

 

When do you run this control, Daily, Day of Use or with each patient?

 

Dan

 

Mabel,

 

When do you run this control, Daily, Day of Use or with each patient?

 

Dan

In the USA you have to run a positive and negative control with gel cards,i.e., you have to show that the cards react and don't react.

It is to be run each day of use.

As Anna, mentioned above ''You need to use a control that is equivalent to the reagents you are controlling''.

that is to say, from the same manufacturer of your Anti-D. The Rh control contains everything that is present in the anti-D typing sera except the anti-D.

If Rh control is not available then you can use from 6-8% Albumin Because the Albumin added to the Rh control is about 6-8%. And as David said above,The control is necessary (especially in apparently group AB positive patients).

Another application is to use as a negative control when testing a Du or Weak D.

 

 

Edited May 7, 201411 yr by Abdulhameed Al-Attas