How do you handle rule outs on a future work up when the patient has a previous known antibody. Currently we require 3 homozygous (if possible)  rule out cells for a new antibody, but only one homozygous rule out for all significant antibodies on future work ups. I was wondering what everyone else does in this situation 

If we can't identify the antibodies off the panel and enzyme, we have a 2nd panel with a further 11 cells. Occasionally we have used the 3 cell D-neg screen too. Usually these 28 cells (plus 11 enzymes) will give us the answer. But then we send all of ours away to our reference centre for confirmation, so it doesn't really matter... 

I might not have been clear with my question. Say the patient has a history of Anti Kell. The first time we identify the antibody we use the rule of 3. 3 positives to rule in and 3 negatives to rule out. On repeat work ups. We only require 1 homozygous negative to rule out significant antibodies. I want to know if others always use the rule of 3

We do the old 3 x 3 rule, but someone recently pointed out that the statistical basis for this is to rule in a particular antibody --- which makes sense to me.  After all, for most negative screen patients, we are ruling out all significant antibodies with only one or two cells.

(Having said that, our system does also require at least one homozygous cell to rule out those antibodies that show dosage.) 

I am not sure why you would require 3 in one case but only 1 in another.  In fact, a patient that has been known to produce a significant antibody has probably been transfused, and is likely to produce others, so it seems as though you would want to be more careful with a repeat ID and rule outs at a later time.\

Scott

We follow the same process for antibody identification whether it is being done the first time or the 21st time on a patient.

On subsequent workups, we no longer "rule-in" the antibody.  We just pick selected cells to rule out anything else, and our same "ruling-out" rules apply.

Do any of you guys extend the dates between your antibody ID workups for a long term inpatient receiving blood.  Or continue to work it up with every type and screen every 72 hours?

 

 

We do as Terri does, exceept for solid phase we cant "select" the cells, so a whole panel is run.

Also, if the current antibody screen pattern matches the previous antibody we do not do new workups.  A new workup is done a) if an unexpected incompatible xm is encountered or (b) the current antibody screen reactivity does not match the identified antibody (ex. prev. anti K, but a K neg screen cell is now positive) or  c)  if the previous antibody was a non-specific antibody, or clinically insignificant antibody, and we wish to interpret the current screen as cllinically insignificant .  Warm auto's are considered on a case by case basis, but in general a workup is done with each new patient admission.

6 hours ago, tbostock said:

On subsequent workups, we no longer "rule-in" the antibody.  We just pick selected cells to rule out anything else, and our same "ruling-out" rules apply.

Same as tbostock, for rule-outs we have a guideline on what is acceptable 1x and 2x.

If I have a previous history of an antibody I run selected cells.  If possible I will r/o additional specificities with one homozygous cell for those abs which exhibit dosage.  As discussed above, we r/o everything with a negative absc/or one homozygous cell.

We rule in using the 'rule of 3', but rule outs are done with 2 homozygous cells whenever possible. We do not re-ID known antibodies but continue to do 2 homozygous ruleouts every time we see the patient or every 72 hours, whichever comes first.