:mad:Hello there. We just missed Anti-D by using capture R in Galileo in our QC survey sample. It is reaaly frustrating missing Anti-D. Have you had the same problem before using capture R and Galileo? We also had the AB+ patient typed as A+.

CAP survey antibody samples are typically 3-4+. It would be difficult to believe that a properly working analyzer -- or for that matter, any other methodology -- would miss it without some human intervention or major malfunction.

Sometimes with automated instrumentation, it's hard to mimmick a patient with a mock sample, and the analyzer could have gotten comfused.

1. Did your analyser controls for Capture-R work ? (i'm presuming they did- or the results would have been invalidated)

2. Are you using 3 cell or4 cell screen?

3. Check your images- to ensure there is no excess saline in the wells.

4. Find out from your QC provider what IgG subclass the anti-D control was ( Immucor maintain that Capture-R does not detect IgG subclass 4 antibodies..which are designated as not being significant).

5. Did you repeat test the QC?...if you don't have any more sample- ask the QC provider if they can send a further sample to test.

Answer to your question...yes.

What was the source of your QC survey sample? Was it a CAP survey? You need to find out the source of the anti-D used for the survey and how strong it was by other methodologies.

marilyn m

Hi Frahman,

I have now been informed by the company that my missed antibodies were due to storing our phosphate buffered saline in a cold room (they were removed to room temp at least 3 days prior to use). Apprently cold storage of PBS causes PH stratification and therefore affects antibody detectability depending on where the PBS was drawn from for the wash phase (apparently we are the only UK site that does this). This effect is reversible by good mixing prior to use, however the moral of the story is to make sure all reagent storage conditions are strictly adhered to.

All my controls have all been fine during the testing phases.

Please could you tell me if you store your PBS like this too, would be very helpful to know.

Hi Frahman,

I have now been informed by the company that my missed antibodies were due to storing our phosphate buffered saline in a cold room (they were removed to room temp at least 3 days prior to use). Apprently cold storage of PBS causes PH stratification and therefore affects antibody detectability depending on where the PBS was drawn from for the wash phase (apparently we are the only UK site that does this). This effect is reversible by good mixing prior to use, however the moral of the story is to make sure all reagent storage conditions are strictly adhered to.

.

I'm confused. Why would storage of PBS have an effect on antibody identification? What are you washing?

Anna:confused:

Hi Frahman,

I have now been informed by the company that my missed antibodies were due to storing our phosphate buffered saline in a cold room (they were removed to room temp at least 3 days prior to use). Apprently cold storage of PBS causes PH stratification and therefore affects antibody detectability depending on where the PBS was drawn from for the wash phase (apparently we are the only UK site that does this). This effect is reversible by good mixing prior to use, however the moral of the story is to make sure all reagent storage conditions are strictly adhered to. .

I'm confused. What are you washing exactly?

Anna:confused:

Edited April 23, 200916 yr by galvania
posted twice

The automation uses PBS to wash the solid phase plate after incubation. It is possible that an incorrect pH could cause antibody-antigen disassociation

It is also important to run the samples soon after receipt. I believe the CAP survey instructions state to process immediately. We have found that the risk with delayed processing is not so much hemolysis, as stated in the instructions, as it is weaker reactions with the antibodies.