RABIT Methodoloy 23.1 Principle. Detection of growth the RABIT system is achieved by adding the prepared test sample to a culture medium in impedance cells (working volume2 ml to 10 ml). Impedance cells are inserted in the RABIT incubator modules which maintain the selected incubation temperature while recording conductance measurements across the cell contents. Microbial utilisation the culture medium during growth produces conductance changes which are presented graphically by the accompanying software. A positive result is recorded automatically when the rate of conductance change exceeds a threshold selected by the operator. In tested in el with the conventional methodology using an equal number ofreplicates 2.3.2 Single Stage RABIT Procedure. An initial tenfold dilution of each test sample was prepared in MRD as described above. After standing for 30 minutes, 100 x 5 ml aliquots were transferred to equal volumes of impedance medium 1 in sterile Scientific Limited, G50001) supplemented with0.5 g sodium lauryl sulphate per litre and was prepared at double strength. RABIT cells were connected to the system and incubated at 30°C for 24 h, during which a positive test result was recorded if the rate of conductance change exceeded 10 us in three successive 6 minute intervals. To provide confirmation of RABIT test results, the contents of each incubated impedance cell were used to stab inoculate a 10 ml tube of VRBGA, which was incubated and interpreted as described previously