TABLE 1.

Criteria for positive or negative result.

	Clearly positive	Clearly negative
Criteria	1. At least one of the test groups* exhibits a statistically significant increase in the assay endpoint compared to the concurrent negative control	1. None of the test groups* exhibit a statistically significant increase in the assay endpoint compared to the concurrent negative control
	2. Any of the results are outside the distribution of the historical negative control data (e.g., 95% control limits)	2. All results are inside the distribution of the historical negative control data (e.g., 95% control limits)

*Test item, test article or test group: the solution, suspension, or other preparation of the NM added to the test; a test group would be one dose sample among several of the samples in the assay.

“Historical control data” refers to accumulated data from previous experiments.