Scheme 2A Cytotoxic Crossmatching

1
Scheme 2ACytotoxic Crossmatching
2
Scheme Summary

• 28 test sera AB negative control
• Participants own positive control
• 5 distributions of two cells
• Report results within 10 days
• 2008 34 participants

3
Methodology

• Incubation times
• pre C 20 to 60 minutes
• post C 25 to 120 minutes
• 14 different combinations 30 60 and 60 120
• Visualisation of dead cells
• PI, EB/AO, Flouroquench, Stain fix, Eosin
• Beaded cells
• 40 - 50 of laboratories
• 21 no results returned
• Viability (11), technical failure (6),
  staff shortage (4)

4
Sera Distributed in 2008

• Control AB serum
• 6 hidden AB serum
• 11 sera with CDC defined specificities duplicated
  on the tray

5
Cells Distributed in 2008
6
Code Breaking
7
Code Breaking
8
Penalty Point Scoring System for 2008
Missing a positive crossmatch reported by 5
penalties gt75.01 of labs Missing a positive
crossmatch reported by 3 penalties gt50.01 -
75 of labs Missing a positive crossmatch
reported by 1 penalty gt25.01 - 50 of
labs Missing a positive crossmatch reported
by 0 penalty gt15.01 - 25 of labs Finding
positive a crossmatch reported as 5
penalties negative by 75.01 of labs A report of
a void result 1 penalty PP labs with more
than 10 of the maximum available penalty
points PPP PP on 2 occasions in any 5
consecutive cycles
9
Performance Table

• First Cycle
• Range 2 to 53
• Median 10
• PP 28,34,34,41,44,53
• Second Cycle
• Range 0 to 48
• Median 6
• PP 28, 33, 48
• Third Cycle
• Range 0 to 45
• Median 1
• PP 30,35,35,40,45

• Fourth Cycle
• Range 0 to 36
• Median 2
• PP 32, 36
• Fifth Cycle
• Range 0 to 116
• Median 2
• PP 51, 116
• 18 occasions PP
• 3 labs PP
• 6 labs PPP

10
Reproducibility and Negative Control Analyses

• Hidden Negatives
• 6 hidden negatives
• Number of false positives 30 (1.6)
• Acceptable performance for 2008 is gt90
• Two labs failed (85 and 67)

• Reproducibility
• Test sera paired with replicates
• Acceptable performance for 2008 is gt90
• Five labs failed (84,85,85,86 and 90)