PBryant

We routinely screen using both LISS and gel methods and perform a DAT by tube method. Recently we had been asked by a customer to perform the autocontrol in Gel so as to duplicate their results. Our tube DAT was negative----and usually will be unless the autocontrol in Gel is strongly positive (3+ or more). Our tech performed a DAT in Gel (1+) and by tube (negative). An eluate, tested by tube method, was negative. Out of curiousity we then performed an eluate in Gel and it was also negative. Routinely we do not perform eluates in gel. The patient did have an alloantibody (Lea) and units were crossmatched using the gel IgG card. I tend to agree with the thinking that the gel system is too sensitive to give clinically meaningful DAT reactions at 1-2+.

Sandra, We have also experienced problems with the Immucor Fetal Bleed Screen and you are correct when you stated they will acknowledge the problem over the phone. We had two cases this weekend of positive screens with negative K-B stain. Both patients were Du negative and DAT negative. One case was resolved by retesting and using manual washing technique instead of using our cell washer. The other case stayed positive inspite of the manual wash. It has been noted on the K-B stain for this patient that there was a marked presence of WBCs and platelets. Review of the CBC results did show and elevated WBC count and a normal platelet count. The immucor representative as ked that we send them the sample involved in the false positive so we will see what they can find out.

We do not get any of the adsorbed sample returned and so our policy states we do not repeat the xm for DAT positive patients in which adsorbed plasma was used by the reference lab for xm. So sometimes we accept the xm and sometimes we don't. In all cases we confirm ABO,Rh and antigen type (if we have the typing reagent available).

We have, in special circumstances, sent the banded sample. We keep a portion of the sample(s) sent for repeat and/or additional xm testing.

Yes, very helpful. I had not considered the accreditation aspect.....good point. I think we will probably continue to confirm the antigen type though. Error in antigen typing has been found amoung our own staff and if I recall correctly one of my coworkers stated that they have found an error once in a reference tested unit.

Our current policy states that crossmatches and antigen typing will be repeated on all sendout reference samples if the DAT is negative and "absorbed" serum was not used for original testing. I can possibly understand checking the antigen types but why the crossmatch? Is this a standard practice at blood banks using reference lab services? Is this a liability issue? Why would the reference lab results not be the test of record?