ISO 10399:2017规定了确定两种产品样品之间是否存在可感知的感官差异或相似性的程序。该方法是一种强制选择程序。无论差异存在于单个感官属性还是几个属性中，该方法都是适用的。 该方法在统计上不如三角形测试（ISO 4120中描述）有效，但更容易由评估者执行。 即使差异的性质未知（即，它既不确定样本之间差异的大小也不确定方向，也不确定导致差异的属性的任何指示），该方法也是适用的。该方法仅适用于产品相当均匀的情况。 该方法对于 a)确定 要么是可察觉的差异结果（duo-trio差异测试），或 例如，当成分、加工、包装、处理或储存发生变化时，不会产生可察觉的差异（相似性的duo-trio测试），并且 b)选择、培训和监测评估员。 描述了该方法的两种形式: -恒定参考技术，当评估人员熟悉一种产品时使用（例如来自常规生产的样品）； -平衡参考技术，当一种产品不比另一种产品更熟悉时使用。

ISO 10399:2017 specifies a procedure for determining whether a perceptible sensory difference or similarity exists between samples of two products. The method is a forced-choice procedure. The method is applicable whether a difference exists in a single sensory attribute or in several attributes. The method is statistically less efficient than the triangle test (described in ISO 4120) but is easier to perform by the assessors. The method is applicable even when the nature of the difference is unknown (i.e. it determines neither the size nor the direction of difference between samples, nor is there any indication of the attribute(s) responsible for the difference). The method is applicable only if the products are fairly homogeneous. The method is effective for a) determining that

1. either a perceptible difference results (duo-trio testing for difference), or
2. a perceptible difference does not result (duo-trio testing for similarity) when, for example, a change is made in ingredients, processing, packaging, handling or storage, and

b) for selecting, training and monitoring assessors. Two forms of the method are described: - the constant-reference technique, used when one product is familiar to the assessors (e.g. a sample from regular production); - the balanced-reference technique, used when one product is not more familiar than the other.