Table 2.

Significant differences between stored slides and the fresh cut slide. Only storage conditions and durations with a significant difference are listed. For ER, PR, and HER2, there were no significant differences between the number of positive cases for fresh cut and stored slides, regardless of the storage condition or duration of storage. Kappa, K, measures agreement between the stored and fresh sections.

	Storage condition	Duration of storage	P	K (95% CI)
Ki67	paraffin dipped	1 month	0.02	0.57 (0.33–0.81)
CK5/6	4C	1 week	0.03	0.78 (0.61–0.96)
	−20C	1 week	0.03	0.65 (0.44–0.86)
	−80C	1 week	0.03	0.67 (0.47–0.87)
EGFR	paraffin dipped	1 week	0.005	0.51 (0.31–0.71)
	paraffin dipped	1 month	<0.0001	0.27 (0.09–0.46)
	paraffin dipped	6 months	0.001	0.39 (0.19–0.59)
	−20C	6 months	0.02	0.61 (0.43–0.79)