"Most test-tube" is a unique phrase that relates to scientific experimentation. However, if you're looking to add some variety to your vocabulary, consider using synonyms such as "laboratory-generated," "artificially-created," or "in vitro." These adjectives can be used to describe substances or organisms that are produced in a lab environment, often using test tubes or other equipment. In the field of biology, you might also use terms like "cultivated," "propagated," or "cultured" to refer to cells or organisms that have been grown under controlled conditions. Ultimately, the right word choice depends on the exact context you're working with, so don't be afraid to experiment with different options until you find the best fit.