Testing M-S circuits is a difficult task demanding high amount of resources. To overcome these drawbacks, indirect testing methods have been adopted as an efficient solution to perform specification based tests using easy to measure metrics. In this work, a testing technique using octrees in the measure space is presented. Octrees have been used in computer graphics with successful results for rendering, image processing and space clustering applications. In this paper are used to encode the test acceptance region with arbitrary precision after an statistical training phase. Such representation allows an efficient way to test a candidate circuit in terms of test application time. The method is applied to test a Biquad filter with encouraging results. Test escapes and test yield loss caused by parametric variations have been estimated.