Internal Blind Samples for Blood Bank

[Candace Schiele]

I need to develop internal testing for competency.  How would I go about doing that?  Any suggestions?  I need to "doctor" samples so I can access competency after a missed PT.  Any suggestions would be appreciated.  If you have any SOP's or guides that would be great.  Thank you.

[pinktoptube]

Besides making your own blind samples, couldn't you use a sample previously tested and just take off the identifiers?

[David Saikin]

What kind of samples are you making?  abid's, single or multiple abs?

I usually combine a few abscr neg plasmas for a base.  I then will add reagent antisera (outdated) to accommodate what I want the tech to demonstrate.

I also am not opposed to making DAT+ samples (or could just use IgG check cells).

I do not have a formula for adding antisera to plasma.  Sometimes an entire dropper full and sometimes only a few drops.  It gets a bit dicey when using monoclonal abs as some of these are room temp reacting whereas in the real world the ab reacts at 37/ahg phases.

[ANORRIS]

DAVID...May I borrow your formula...thanx!

[David Saikin]

1 hour ago, ANORRIS said:

DAVID...May I borrow your formula...thanx!

I really don't have a formula.  I just make the stuff up.  Like I said, I use a mixed, absc neg plasma as a base and add reagent abs.  Can't really tell you how much to add.  Sometimes as little as 4-5 drops/4mL is enough; sometimes up to 10 drops.  Depends how avid the ab is.  I also use outdated panel cells as a cell suspension to go with my antibody(ies) in case my tech needs to ag type the "patient".

[Sandy L]

Another thing that I do for positive antibody samples when using outdated antiglobulin reacting antisera:  add a few drops of anti-A,B to turn the plasma into “group O” and then pick a panel cell for the cell suspension.  This would achieve the same thing as David’s mix of absc negative patient plasma’s.  Patient’s with positive absc’s are also a good source for unknowns.  Another source, once the reporting deadline for proficiency testing has passed, we re-assign proficiency samples (if quantity permits) as additional competency samples.  We try to get a much mileage as possible so we use these types of unknowns for ABID, antigen typing, titers, antibody screens in gel (automated and manual platforms) and tube testing.

For DAT’s, I will make a mix of outdated IgG sensitized Coombs Control cells and un-sensitized cells (outdated screening cell, etc.) to make a mixed field positive DAT.  Also I save outdated Complement sensitized Coombs Control cells for DAT unknowns.

[AMcCord]

Here are some recipes I use for students (attachment).

You can also get some nice sample kits from Immucor specifically for training/competency assessment. They are part of my standing order - 1 kit a month that is a 'patient' sample for crossmatch and antibody ID. Or another option gives you 1 kit a quarter that is a bit more complicated and which may represent a transfusion reaction workup or tricky antibody ID or something else a little more challenging. Yes, they cost money, but I feel they are good value. And you can usually use each kit for 2 techs (if they don't go overboard on ruleouts). Ortho most likely has similar products. Quotient has a kit with serum samples that I've used - some positive for antibodies and some negative - that is a one time purchase.

Antibody Recipes.docx

[Teristella]

We have used the Immucor Self-Cheks and their other products and enjoyed them. A rep let us try the Quotient competency kit (serum only) which I froze, and they've continued to react well about six months later. Some of them are pretty simple antibodies but you can always mix if you want multiples. I think they make one kit a month.

[John C. Staley]

I had forgotten all about the Immucor Self Checks.  We used them all the time.  If they are still available I highly recommend them.  No need to re-invent the square wheel if you don't have to.

Edited April 10, 2016 by John C. Staley
had another thought.

[Whitney]

How do you define a test system in your labs for competency assessment?  

[pinktoptube]

Test systems have all 3 phases - preanalytical, analytical, and postanalytical. Anything that gives a technical result "Gel method, Tube method, Automation, Kits, etc...".