comb test

noun2

1. •
   (historical) A method of determining racial identity, based on how easily a comb passes through a person's hair.
2. •
   A test for whether a substance should be considered a male sex hormone.

   • In addition to the comb test, physiologists applied assays based on changes in fat deposits, body length and weight, and hair growth, in rats and guinea-pigs. — 1994