Final answer:
Repeat TC tests must be sampled from the same or representative area as the initial test, using a wet swab to collect the sample and spreading it over a TSA agar plate.
Step-by-step explanation:
When conducting repeat TC (total count) tests, which are often associated with microbiological analyses, it is essential to sample in the same area or an area representative of the initial test to ensure consistency and accuracy. Rub the wet swab back and forth firmly over the chosen area of skin to collect the sample. Then, following aseptic techniques, spread the swab over approximately a third of the surface of the TSA (Tryptic Soy Agar) agar plate for bacterial culture and incubation. This process is crucial for identifying potential contamination or conducting quality control checks in various settings, such as medical, pharmaceutical, or food industries.