Jump to content
PathLabTalk

Parallel testing procedures


Recommended Posts

The facility that I currently work at has gone crazy with their rules and regulations. I was wondering if there are any other labs out there that do parallel testing with a patient on blood banking regents. I remember when working in another facility, all we had to do was QC new lots or newly opened bottles. I know that parallel testing is a common procedure in chemistry amongst many other departments, but I never really seen a specific "lot to lot" procedure in a blood bank.

Link to post
Share on other sites


What do you use as a "lot to lot"? Do you only QC them? and do you document that you QC'ed it compared to the previous lot? My job has a chart that they make us fill out when we change lots. It compares old lot QC passing to new lot QC passing. I think that this is not useful because it isn't really proving anything, since you are only running QC, you are not really comparing the lots.

Link to post
Share on other sites
  • 2 weeks later...
What do you use as a "lot to lot"? Do you only QC them? and do you document that you QC'ed it compared to the previous lot? My job has a chart that they make us fill out when we change lots. It compares old lot QC passing to new lot QC passing. I think that this is not useful because it isn't really proving anything, since you are only running QC, you are not really comparing the lots.

I don't compare lot to lot: this is esp true with the rare reagents when you have to purchase from different vendors . . . I just qc all the stuff when I use it. Blood Bank is not generating numbers (like glucose, or K+) wherre you have to have a reasonable amount of similitude for your answers. Mostly we generate interpretations . . . which opens up a large can of worms. There is a new CAP standard that says something about when interpretations are the results are these reviewed before they are released (or something like that) . . . NOT IN THE BLOOD BANK, esp on nights when there is only one person . . . Let's get real.

Link to post
Share on other sites

I agree with both of David's posts, with the following 2 comments:

1. I believe we have to do "Correlation Testing" if your department uses different methodologies. As example, we use the Galileo Echo instrument, but we also something use regular test tube technique (ie: when the Echo is down, when we are busy, etc.) So at least twice a year we test several patient specimens using both the Echo and tube testing to verify that we get the same (or acceptably similar) results regardless of which testing technique was used.

2. Regarding David's comments about "reviewing results": I think we are dealing with terminology here. For example, my BB is OK because when we enter out testing results and our interpretations into our BB computer system, the last step is the to click on the "Verify" button. Of course some techs just simply perform this step automatically, but the true intention is that the user is supposed to review the results and "verify" that the interpretation is correct. (It isn't being "reviewed" by a second person.)

Donna

Edited by L106
Link to post
Share on other sites

We just had a CAP inspection. We do parellel testing with Manual Gel Vs Tube Method for Type and Screen and Antibody ID. Our primary method is Manual Gel and secondary method is Tube. We run several patients and compare ABO RH, Antibody Screen, and Antibody Panel by Gel and Tube. We include two or three positive antibody screen with different antibodies e.g. Anti D, E or K. The CAP accepted the parellel testing.

Link to post
Share on other sites
  • 2 months later...

Reviving this thread with an added question. We compare manual gel (primary method) to tube (backup). What are considered "acceptable" differences as we all know these two methods will not give the same strength reaction with the same specimen? All opinions welcome.

Link to post
Share on other sites

Deny,

We did extensive correlation prior to going live with the gel testing and determined that a 1+ in gel would not show up in tube at all, a 2+ in gel was microscopic in tube, 3+ was 1+ in tube and a 4+ was 2+ or greater in tube. We use these guidelines when we make QC specimens and go our comparison studies. I try to "make" an antibody that will give me ~3+ in gel then expect to get a 1+ in the tube.

My current QC gives me a strong 3+ in gel and a weak 2+/strong 1+ in the tubes...

Link to post
Share on other sites
  • 5 weeks later...

We are also interested in knowing what experiences other Blood Banks have had during their most recent CAP inspections relative to satisfying common checklist question COM.30450. Are the inspectors writing deficiencies if Blood Banks are not doing lot-to-lot verification studies? I'm not talking about correlation studies between methodologies. And I'm not talking about the usual reagent QC that we've all been doing for years. I'm strictly referring to lot-to-lot verifications.

Link to post
Share on other sites
I thought the FDA had to verify potency on all BB reagent lots.

Similar occurs in the EU with CE marking Mabel, but, what the MHRA says is that we have to verify that they work once they have reached the laboratory, incase they have gone off during postage/delivery.

They never have, of course, but we have to show proof.

Link to post
Share on other sites
Looking for more experiences with this topic please. Trying to see what the industry normal differences are among the users here. Thanks.

This sounds pretty lame, but in some cases we expect them not to correlate. Our Tango picks up Anti-K when gel and tube miss it, our gel picks up Anti-E better than on the Tango, and tube testing can miss weak antibodies. We don't use QC samples, we pick random patients and if they do not correlate, we explain why.

Link to post
Share on other sites

I wasn't suggesting that we not do daily reagent QC but that, as long as we do not see any unexpected variation in that daily QC with a new lot, we can assume that the potency that the FDA verified on that lot has not been damaged by shipping, storage and handling. I don't think Chem reagents start out with the same regulatory requirements for "purity and potency" so the logic that applies to them for lot to lot comparisons may not apply to BB reagents.

Link to post
Share on other sites

Regarding "acceptable differences" between methodologies, our Correlation Procedure has a "Comment" at the end of the procedure stating (and haven't had a problem to date):

"It is recognized that the reactions or strength of reactions may not be exactly the same for testing done on XYZ instrument and testing done with XYZ tube technique. It is the responsibility of the Blood Bank Supervisor to evaluate whether any variation is acceptable."

(It reminds me of the last sentence in most of our old job descriptions: "....and any other duty assigned by his/her supervisor.")

Link to post
Share on other sites
  • 1 year later...

I am also struggling with how to interpret COM.30450 in the CAP Common Checklist and how it relates to blood bank transfusion testing.  Are there any more thoughts out there? Are transfusion facilities being cited by CAP for not performing the New Lot/New Shipment Confirmation of Acceptability?

Link to post
Share on other sites
  • 1 year later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Advertisement

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.