Dilute 1:100

Dilute 1:100 is your go-to dilution method

It is both easy and fast. Usually, you want to start with a 1:10 000 dilution first, which is just two 1:100 dilutions in a row.

Measure the most diluted sample first.

By the book

The “by the book” method is to prepare aliquots of 9900 µL diluent and add 100 µL of sample. This works if you have the patience and a bottle-top dispenser or a P10,000 pipette.

Our shortcut

There is a much easier way forward: Add 101 µL of your culture to the 10 mL in a dilution vial. This gives you a 1:100.01 dilution, which is very close to the target of 1:100. Once mixed together, we call it your sample vial from now on.

Procedure to make a 1:100 dilution

Vortex each dilution step thoroughly!

Always vortex thoroughly for at least 10 seconds. Ensure that a clear cyclone/vortex appears.

You must perform proper vortexing to ensure that the transferred bacteria are well-mixed in the prepared dilution. Without proper vortexing, you may get underestimation of concentration and variation between replicates.

Your sample vial is for single use only

Once you run the liquid through BactoBox®, the properties change significantly.

Always discard your sample vial after use!

Need to dilute 1:10 000? Or 1:1 000 000?

Simply repeat the process described above. A 1:100 dilution followed by another 1:100 dilution gives a 1:10 000 dilution. Add another 1:100 dilution and you get a total dilution of 1:1 000 000.

For every single 1:100 dilution you do, add two zeroes to the overall dilution factor.

Measure the most diluted sample first

If you don't know the concentration in your sample vial, it is best to play it safe. Prepare a dilution series as pictured above. First, measure on the most diluted sample. Then, move towards less diluted samples step by step. Stop when the concentration is within 0.5–4 million cells/mL.

Target 0.5–4 million cells/mL for fast results

The more things to count, the faster we are certain about the concentration. Give BactoBox® something to work with and it triggers the Fast results feature ⏩.

Make a dilution series and measure the most diluted sample first. Aim for 0.5–4 million cells/mL.

Is the final dilution factor in your sample vial 1:100?

You might run into conductivity-related errors. Avoid these with a custom diluent.