Table 3.

Stability of Samples and Reagents Used in GM-CSF Autoantibody Assay.

	Concentration (Mean ± SD) μg/ml
Condition / Sample*	Before	After	P Value¶
Freeze-Thaw (x3) †
Low	9.398 ± 0.9	10.46 ± 0.67	0.17
High	37.20 ± 2.44	37.66 ± 1.61	0.77
Short term sample storage‡
Low	9.398 ± 0.9	9.82 ± 0.69	0.56
High	37.20 ± 2.44	38.64 ± 2.18	0.49
Long term sample storage§
Low	9.398 ± 0.9	9.75 ± 0.05	0.54
High	37.20 ± 2.44	38.19 ± 1.10	0.55
Short term reagent storage ║
Diluted PCRS, low concentration	8.45 ± 0.56	7.82 ± 0.75	0.31
Diluted PCRS, high concentration	27.85 ± 1.21	27.79 ± 1.09	0.95

^*GMAb concentration was measured in separate serum aliquots (n=3) from two patients.

^¶P values were determined by comparison of before and after values using Student’s t-test.

^†GMAb concentration was measured in serum samples subjected to freezing to −80°C and thawing at room temperature three times.

^‡GMAb concentration was measured in serum samples before and after keeping at temperature for 6 hours.

^§GMAb concentration was measured in serum samples before and after keeping in −80°C freezer for 3 months.

^║GMAb concentration was measured in aliquots of PCRS diluted to low or high concentration (indicated) before or 6 hours after being kept on the counter at room temperature for 6 hours.