Test code links throughout this Guide refer to the corresponding test in the User's Guide.
Growth is monitored radiometrically in broth media instead of counting colonies.
This method provides much faster results and avoids the potential problem of drugs degrading over a long incubation period. When an antituberculous drug is added to the medium, suppression of growth occurs if the test organisms are susceptible. This suppression can be detected by either a decline or a very small increase of the daily GI output as compared to the control. Interpretation of susceptible or resistant GI is based upon comparison of growth in drug-free media to growth in media containing drug. Results can be used to guide therapy.