I assume you have 1x10-6.3/ml. This is equal to 3.7 TCID50/ml. Then you will need 216.2 ml to get 800 TCID50

TCID50 has to be calculated in a volume of original sample.

You have to express you 1x10-6.3 TCID50 as vol conc. then you will able to calculate you dose

For example, you have 1x10-6.3 TCID50 in 1 ml = 6.3 Lg TCID50/ml

800 TCID50 = 2,9 Lg TCID50 in 1 ml dose

6,3-2,9 = 3,4 Lg will be you DF = 10^3,4 = 2511 times

So, you have to dilute 1 ml of virus stock up to 2511 ml to achieve 800 TCID50 in 1 ml = dose

I have the similar question to calculate the dose per mouse. However I cannot understand the answer of Daniil, (what is Lg?if 800 TCID50 means 800 times of the volume. how can I inject 800ml/dose/mouse?????) anyone have another simple explaination? Help me, please!

Hi Thi,

TCID50 is a dose of infectious agent which induces infection in 50% of tissues samples (wells etc). For example, if we infect a couple of cell cultures by 1 TCID50 per sample than 50% of wells will be infected other not.

Ordinary, the TCID50 is expressed as some activity per volume (like a concentration). Foe example, the Infectious dose of a virus stock is 1 500 000 TCID50/ml.

So, we have to know dose activity as well as dose volume to infect an animal.

You can quantify a virus in linear or log scale. For example, 800 linear TCID50 = 2,9 Log TCID50. Those utilize different arithmetic calculation approaches. You can select one of them, which is more suitable for you.

Linear scale calculation example:

You have virus stock 1 500 000 TCID50 in 1 ml (stock)

You have to infect animal by 800 TCID50 in 0,1 ml (dose)

(1) Lets calc working solution into 1 ml volume with 800 TCID50/0,1 ml: 800 TCID50 *1 ml /0,1ml = 8 000 TCID50 in 1 ml is your ready to use (working) solution with dose 0,1 ml per animal.

(2) Next, calculate DF to achieve desired activity 8 000 TCID50 in 1 ml: 1 500 000/8 000 = 1875 times. You have to dilute the virus stock 1875 times to made working solution.

For example,

First dilution step is 1:18,75 (1 ml of stock fill up to 18,75 ml by diluent)

Second dilution step 1:10 (final 1:187)

Third dilution step 1:10 (final 1:1875)

I hope it will be helpful,

Daniil