Full crossmatchs needed?

[Seveets]

Our policy states that FULL crossmatches (through the IAT phase) are needed when a patient has an unexpected antibody, a history of an unexpected antibody or a positive DAT.

Can someone talk me through or point me in the right direction (which Standard) to why a full crossmatch is needed when a patient has a Negative antibody screen but a Positive DAT ( most likely due to either a warm auto or drug induced -- patient has never been transfused.)

[Karen Olsen]

With our current procedures, we wouldn't even be aware of a positive DAT with a negative screen unless it was specifically ordered by the physician. We would do IS crossmatches with a negative screen. A DAT is a reflex test with a positive Auto Control run in conjuction with the ABID panel. Therefore we would do AHG crossmatches because of the positive screen, not necessarily because of the positive DAT.

[Jane]

We wouldn't know either unless a DAT was ordered separately. Our policy for the crossmatch through AHG just applies to patients with antibodies (past or current).

[Seveets]

Thank you Karen and Jane,

We wouldn't know either but it happened to me last week and I DID NOT do the full crossmatches. My actions caused an internal incident report and a product deviation report to be filed.

I wanted to know about the reasoning behind doing full crossmatches is this particular situation but as of yet have not come up with them, nor has the supervisor.

[Eagle Eye]

How did you know that pt's DAT was positive? Patient has history of positive DAT? Our procedure wouldn't pick up positive DAT unless historically patient has positive DAT. WE use gel screening and if screening is negative(and no history of antibody) we do IS XM. In that case we wouldn't know if patient has positive DAT, Unless patient comes back with transfusion reaction.

If patient has history of positive DAT and we identify any antibody we will do full crossmatch otherwise I enter a comment in the LIS for the staff that IS XM needed as per Dr.X.

[Seveets]

How did you know that pt's DAT was positive? If patient has history of positive DAT and we identify any antibody we will do full crossmatch otherwise I enter a comment in the LIS for the staff that IS XM needed as per Dr.X.

Hi, Patient was brand new with no history -- 39 year old male with no signs of bleeding and a Hct of 27. I did a DAT on my own with the idea he might have WAIHA. It was 2+ in gel with a negative ABS. I did not do an elution because the patient was never transfused = warm auto or drug induced.

In my head, I had ruled out all major antibodies, and thus did not need to do full crossmatches.

I was cited for not following the SOP.

[bpkelly]

We dropped doing a full crossmatch on people with positive DATs unless you have tested the specimen you are currently using and it is positive. If you don't know and don't test- no full crossmatch required.

[rcurrie]

DATs are like Bill Clinton's gays in the military policy- don't ask, don't tell. But, when you do one, you are stuck with dealing with the results. I had a tech do a DAT "just for the heck of it" and it was positive. She was miffed when I gave her the specimen back to follow-up with an elution and ID. She said, "We would never have known there was an antibody if I hadn't done the DAT." I said, "Exactly." She won't do that again. What did she find? An antibody to a low incidence antigen that she couldn't identify after 2 days. Resolution: crossmatch through AHG. Chances are, if we had never seen the DAT and used electronic crossmatches, the patient would never have been transfused with antigen positive blood. Even if she had, chances are there would have been no reaction. Remember- we stopped doing DATs routinely just to keep from dealing with junk antibodies and complement.

BC

[Sandy Jo]

We do not perform a full AHG crossmatch based on a positive DAT. If prior or current clinically significant antibody detected, or unidentified antibody, that would warrant an AHG crossmatch. If DAT was run (based on positive autocontrol or on physician order) and was positive, an elution may be performed, depending on whether the patient has been transfused recently (up to 6 months). If an elution was done and a clinically significant antibody was identified, than we would perform an AHG crossmatch.

Sandy R.

[DFields]

What if the + screen is found due to RhIg anti-D or cold antibody (not clin. significant)-

do you allow I.S. crossmatch?

Do you do T&S conversion and xm units for those + screens?

If using electronic xm would it let you do that if clin. insignif. antibody is identified??

[LAS]

Once you have detected the pos DAT, then you are obligated to investigate it.

"don't ask, don't tell". Love it!