Q.Diluting fluid used for total RBC count is

Step 1. A diluting fluid for blood cell counting must keep the target cells intact while diluting the sample to a countable density.

Step 2. For a total RBC count, the fluid used is Hayem's solution, which is isotonic with blood - meaning it does not disturb the internal water balance of the red cells - so the red cells stay whole and haemolysis (bursting) does not occur; blood is diluted 1:200 with it and counted under the 45x objective.

Step 3. Turk's solution (option a) is instead used for total WBC counts - it contains glacial acetic acid, which deliberately lyses red cells so they don't interfere with the white cell count, plus gentian violet, which stains the white cell nuclei.

Step 4. Toisson's solution (option b) and Folin phenol reagent (option d) are not the fluid described in this chapter's RBC-counting method - Folin phenol reagent is in fact a reagent used in protein estimation, unrelated to cell counting.

Match the diluting fluid to its counting purpose: Hayem's keeps RBCs intact (used for RBC counts), Turk's deliberately destroys RBCs (used for WBC counts).

• Swapping Hayem's solution (RBC count) and Turk's solution (WBC count) - the two work by opposite actions on the red cell.
• Assuming any 'diluting fluid' listed is interchangeable, without checking whether it preserves or lyses the red cells.