mpmiola

Dear Malcolm,
We did molecular analysis, which confirmed the presence of the O in the homozygous state.
Interestingly, only one class of antibodies is not being produced.
Thanks for contributing.

The LW can also be confirmed after treatment with DTT.
I agree with Malcolm Needs, I think this scenario an auto-anti-LW or auto-anti-D is more likely.

IgG blocking study was performed by C.Wong at CarterBloodCare in 2001. It was published as an abstract in Transfusion. The reference is "Evaluation of a Method to Prepare IgG-Sensitized Red Blood Cells for Phenotyping" 2001- Vol.41, Supplimen:110S 
Outline steps are:
1. Wash red cells to be treated 3 times with isotonic saline
2. After the last wash resuspend the red cells to 3-5%
3. In a separate tube add 20 drops of the washed red cells
4. Centrifuge 1 min
5. Remove and discard supernatant, be careful not to disturb the red cells
6. Add 20 drops of IgG to the cells button
7. Incubate at room temperature for 15-30 minutes
8. Centifuge for 30 sec
9. Remove supernatant
10. Wash at least 4 times with isotonic saline
11. Perform IgG DAT on washed,treated cells. Be sure to include a 6% albumin control to verify the immunoglobulin coating has been removed.
If the DAT is negative the cells are ready for typing.
If the DAT is positive repeat the treatment. No more than three times.
*This procedure works best for initial DATs no stronger than 2+
**This procedure can be used on EGA treated cells.
***This method peserves the KELL system antigens if used with non EGA treated cells.
If you have any questions please email me at dwebber@carterbloodcare.org
 
 

I've used this technique successfully in detales see the article:
 
"A quick and simple method for phenotyping IgG-sensitized red blood cellsT.S. SERERAT, D. VEIDT, AND A. DUTCHEDPositive (IgG) direct antiglobulin test (DAT) reactivity ranging from weakly positive to 2+ can be eliminated using a simple “blocking” technique with anti-IgG. This method can be used for antigen typing DAT-positive red blood cells that require the antiglobulin technique. Immunohematology 2000;16:154–156."

There is an article titled "Debunking the 30-Minute Rule" in the May 2010 edition of the AABB News.  The 30-minute rule ignores the laws of thermodynamics and is unacceptable today.  The temperature must be taken on all units returned unused to determine if the unit can be re-issued for transfusion. 
 
You didn't mention the pneumatic tube transit time.  It is likely the reason why units are exceeding 10C as Deny Morlino mentioned.

There's an interesting study in the June 2013 Transfusion (Thomas, Hancock and Cardigan, The 30 minute rule for red blood cells: in vitro quality assessment after repeated exposure to 30°C (pages 1169–1177)) http://onlinelibrary.wiley.com/doi/10.1111/j.1537-2995.2012.03890.x/pdf
 
 
I'm not sure if the NHS formalized the 30 minute rule (FDA and AABB haven't, as noted above,) but the authors write like it's a rule, and for their study they tested some temperature excursions: core temp to 10°C and multiple 30°C excursions for 30 or 60 minutes.
From the abstract:
CONCLUSIONS: There was no evidence of significant damage to RBC after exposure to 30°C for three
periods of 30 minutes. Multiple exposures of 60 minutes caused limited damage but this was within current regulatory limits if there were three or fewer exposures, suggesting that a 60-minute rule may be feasible.
 
Hopefully we see a few more studies like this, because as the original poster noted we as an industry are (likely) wasting a lot of acceptable units.

I used to work for a blood center reference lab and we were not be able to use rare units that we 'lost' this way. We made a very huge effort to go label freshly collected units every day with 'RARE - please filter' tags but if they were not caught before the 5 days, we could not have them leukoreduced.

See attached; this is all I could find.
Discharge Hgb Level as a Marker for Utilization, Transfusion Journal Nov 2012.pdf