Final answer:
Streak plate method and Differential White Blood Cell Count are techniques used for samples with high cell density. Streak plate subcultures should display well-separated colonies, while blood smears aim for distinct cell identification. Indirect cell counting methods like turbidity measurement with a spectrophotometer can also indicate high cell density.
Step-by-step explanation:
When working with samples suspected of high cell density, techniques such as the streak plate method are employed to separate a mixed culture into individual colonies. This allows for the creation of pure cultures by diluting the cells and spreading them over the agar surface in stages. Streak plate subcultures should show individual colonies, well separated from each other, and possibly reveal different types of colonies when mixed cultures are used.
Similarly, for blood samples, a Differential White Blood Cell Count (Diff) requires making a blood smear with a goal of achieving a single layer of cells that are easily distinguishable. The smear is then stained with Wright-Giemsa stain so that a technologist can perform a differential cell count by scanning and identifying each white blood cell type.
For indirect cell counts, techniques such as measuring the turbidity with a spectrophotometer are often used. This method assesses cell density within a culture by relating light transmission through the bacterial suspension to cell count. High turbidity indicates high cell density.