Table 3.

Verification of stability of Gal antigen-positive reference materials.

Storage conditions of the samples#	Gal epitopes (×1014/mg)
# of months stored at −20 °C
1	6.06 ± 0.20
6	6.71 ± 0.10
12	6.97 ± 0.20
# of times of freezing/thawing
1	6.49 ± 0.62
3	6.73 ± 0.15
5	6.48 ± 0.23
# of days stored at 4 °C
3	6.40 ± 0.49
7	6.31 ± 0.40
14	6.16 ± 0.49
30	5.87 ± 1.02
# of days stored at 25 °C
3	7.49 ± 0.72
7	6.70 ± 1.83
14	7.10 ± 1.19
# of days stored at 37 °C
1	6.24 ± 1.31
3	4.34 ± 0.81*
7	4.67 ± 0.69*

^*p < 0.05 compared to the identified value [(6.66 ± 0.83) × 10¹⁴/mg] of Gal antigen-positive reference material (stored at −20 °C); ^#n = 3.