Question

5) (6pts) You were asked to perform a cell count from a vial of cells. In order to do so, you mixed 10uL of cells from your vial and 10uL of trypan blue in a tube and then loaded 10uL onto a hemocytometer. The image below shows photographs you took of each quadrant on the hemocytometer. After counting cells in each quadrant, answer the following questions below and SHOW OR EXPLAIN YOUR WORK PLEASE.

A. (1pt) What is the live vs dead cell count for the upper left quadrant? 109 live cells vs. 5 dead cells

B. (1pt) What is the live vs dead cell count for the upper right quadrant? 46 viable cells vs. 48 dead cells

C. (1pt) What is the live vs dead cell count for the lower left quadrant? 62 viable cells vs 8 dead cells

D. (1pt) What are the viable cells per mL for this sample?

I was thinking you would do this, but I'm not sure:

1. (217 viable cells/ 3 quadrants) * 2 * 10^4 =

E. (1pt) What are the dead cells per mL for this sample?

I was thinking you would do:

1. (61 non-viable cells/ 3 quadrants) * 2 * 10^4 =

F. (1pt) What is the % viability for this sample?

G. (1pt) What is the % death for this sample?

Answer 1

Dilution Factor= 20 uL/10 uL= 2

Answers to question A to C are already provided. As the images are not provided, the cell counts provided in A, B and C will be used for calculation of D, E, F and G.

Viable cells are the unstained cells while dead cells are the stained cells that take up Trypan blue.

A. Live (viable) cell count in upper left quadrant= 109 cells

Dead cell count in upper left quadrant= 5 cells

B. Live (viable) cell count in upper left quadrant= 46 cells

Dead cell count in upper left quadrant= 48 cells

C. Live (viable) cell count in upper left quadrant= 62 cells

Dead cell count in upper left quadrant= 8 cells

D. Viable cell count/mL= (Average number of live cells in 3 quadrants/3) X Dilution factor/ 10^-4 cm-3

10-4 cm-3= 1.0mm X1.0mmX 0.1mm

Viable cell count/mL= (109 + 46 +62/3) X 2 /10^-4 cm3= 72.33 X 2/10^-4= 1.45 X 10⁶ cells/ mL.

E. Dead cell count/mL= (Average number of dead cells in 3 quadrants/3) X Dilution factor/10^-4 cm-3

Dead cell count/mL= (5+48+8/3) X 2/10^-4 cm-3= 20.33 X 2/10^-4= 4.07 X 10⁵ cells/ mL.

F. % Viability of cells in sample= Total number of viable cells/mL/Total number of cells (dead+live) X 100

There is no dilution before addition of Trypan blue.

% Viability= (1.45 X 10⁶ cells/ mL)/[(14.5 + 4.07) X 10⁵] X 100= 78.02%

G. % Dead cells in sample= Total number of dead cells/mL/Total number of cells (dead+live) X 100

% Death= (4.066 X 10⁵ cells/ mL)/[(14.5 + 4.07) X 10⁵] X 100= 21.895%= 21.9%