text: Besides the above-mentioned two most commonly used family of techniques, a wide range of protocols were developed to measure chemotactic activity. Some of them are only qualitative, like aggregation tests, where small pieces of agar or filters are placed onto a slide and accumulation of cells around is measured.
  In another semiquantitative technique, cells are overlaid the test substance and changes in opalescence of the originally cell-free compartment is recorded during the incubation time.
  The third frequently used qualitative technique is the T-maze and its adaptations for microplates. In the original version, a container drilled in a peg is filled with cells. Then the peg is twisted and the cells get contact with two other containers filled with different substances. The incubation is stopped by resetting the peg and the cell number is counted from the containers.
  Also, lately, microfluidic devices have been used more and more frequently to test quantitatively, and precisely, for chemotaxis.