Detect coliforms/E. coli with the convenience of a long-read window


Simultaneously detects both total coliforms and Escherichia coli; positive results have a distinct magenta color. Results valid through 48 hours.



  • Distinct magenta color is easy to see.
  • Ease of use simplifies training.
  • Unit-dosed packaging eliminates media preparation.
  • Quality Control (QC) procedure can be done in 15 minutes.

  • Less than 1 minute of hands-on time.
  • Detects coliforms and E. coli simultaneously in 24 hours or less.
  • No confirmations needed.
  • No glassware cleaning or colony counting.


  • Definitive results at 24 hours; can be read up to 48 hours.
  • Identifies E. coli specifically, eliminating unneeded public notification due to non-target organisms.
  • Suppresses up to 2 million heterotrophs per 100 mL.
  • Eliminates the subjective interpretation found in traditional methods.
  • Detects a single viable coliform or E. coli per sample.
  • Minimizes evening and weekend work.
  • Up to 12-month shelf life at room temperature.

  • The Colisure Test can be used for presence/absence (P/A) or quantification testing.
  • Quanti-Tray provides counts to 200/100 mL without dilutions.
  • Quanti-Tray/2000 provides counts to 2,419/100 mL without dilutions.


How the Colisure Test works

The Colisure Test uses proprietary Defined Substrate Technology (DST) nutrient indicators CPRG and MUG to detect total coliforms and E. coli. Coliforms use the β-galactosidase enzyme to metabolize CPRG and change it from yellow to magenta. E. coli use β-glucuronidase to metabolize MUG and create fluorescence.




How to use


Step 1

Add reagent to sample and incubate at 35 ± 0.5°C for 24 hours.

Step 2

Read results:

  • Yellow = negative
  • Magenta = total coliforms
  • Magenta/fluorescent = E. coli


Step 1

Add reagent to sample.

Step 2

Pour into Quanti-Tray (counts from 1–200) or Quanti-Tray/2000 (counts from 1–2,419).

Step 3

Seal in Quanti-Tray Sealer and place in incubator at 35 ± 0.5°C for 24 hours.

Step 4: Quanti-Tray

Quanti-Tray—Read results:

  • Magenta wells = total coliforms
  • Magenta/fluorescent wells = E. coli
  • Count positive wells and refer to MPN table

Step 4: Quanti-Tray/2000

Quanti-Tray/2000—Read results:

  • Magenta wells = total coliforms
  • Magenta/fluorescent wells = E. coli
  • Count positive wells and refer to MPN table

Frequently asked questions

Is the Colisure Test approved by the U.S. EPA?

Yes, the Colisure Test is U.S. Environmental Protection Agency (EPA) approved as a method for total coliforms and E. coli detection in drinking water and for E. coli detection in groundwater.

What is the detection limit of the Colisure Test ?

The Colisure Test detects coliforms and E. coli at 1 organism/100 mL.

What is the shelf life of the Colisure Test ?

The shelf life for the Colisure Test is up to 12 months from date of manufacture.

What are the recommended storage conditions for the Colisure Test ?

Is there a comparator for the Colisure Test ?

There is no comparator for the Colisure Test. For comparison, use a negative control when interpreting results.

Why is the read window 24–48 hours?

The reagent system was designed to suppress non-coliform CPRG or MUG positive bacteria for at least 48 hours. If incubation extends past 48 hours, it is possible that such bacteria could overcome the reagent and react with CPRG or MUG. When incubation exceeds 48 hours, only negative results are valid. Positive results must be confirmed.

What are the disposal requirements for a Colisure Test sample?

Check with your local, state, and/or federal authorities for proper disposal of bacteriological biohazard materials at your facility.

Can samples be read after 48 hours?

If an inoculated Colisure Test sample is inadvertently incubated over 48 hours, lack of red to magenta color is a valid negative test; a red to magenta color after 48 hours is not valid and should be repeated.

Can samples be read before 24 hours?

An inoculated Colisure Test sample that is positive for coliforms and E. coli before 24 hours is a valid positive test for both coliforms and E. coli. If the sample is positive before 24 hours for coliforms only, the sample is a valid positive test for total coliforms. However, the sample should be incubated for a longer period (at least 24 hours, but not greater than 48 hours total time) to determine whether E. coli are present.

Can I use the Colisure Test with Quanti-Tray and Quanti-Tray/2000?

Yes, when using the Colisure Test with Quanti-Tray, Quanti-Tray/2000 or any multiple-tube format, be sure to use IDEXX Antifoam Solution or a vessel with antifoam.

What should the color and consistency of the Colisure reagent powder be?

The Colisure reagent powder should be tan in color; it should be dry and free-flowing. Any concerns about the color or integrity of the powder should be directed to IDEXX Technical Support.