Quanti-Tray® & Quanti-Tray®/2000

Take the guesswork out of bacterial counts

Drinking Water Bottled Water Recreational Water Pool-Spa Water Wastewater Groundwater

The IDEXX Quanti-Tray® and Quanti-Tray®/2000 provide easy, rapid and accurate counts of coliforms, E. coli, enterococci and Pseudomonas aeruginosa. The IDEXX Quanti-Tray and Quanti-Tray/2000 are semi-automated quantification methods based on the Standard Methods' Most Probable Number (MPN) model.

  • The Quanti-Tray® Sealer 2X automatically distributes the sample/reagent mixture into separate wells.
  • After incubation, the number of positive wells can be converted to an MPN.
  • Quanti-Tray provides counts from 1–200/100 ml.
  • Quanti-Tray/2000 counts from 1–2,419/100 ml.
  • Total hands-on time is less than 1 minute per test.


The MPN Generator Programme makes calculating and recording your test results even easier.

Quanti-Tray/Quanti-Tray 2000


Call 1300 4 IDEXX or email water@idexx.com.

Quanti-Tray: Confidence in quantification




  • No media preparation.
  • No pipetting.
  • No dilutions (for counts to 200/100 ml or 2,419/100 ml).


  • Less than 1 minute of hands-on time.
  • Results in 24 hours or less.
  • No confirmation necessary.


  • Detects down to one organism per 100 ml.
  • 95% confidence limits better than 5- or 10-tube Most Probable Number (MPN).
  • 95% confidence limits better than or comparable to membrane filtration (MF).

Cost Effective

  • Minimal equipment to purchase and maintain.
  • No glassware to purchase and clean.
  • Minimal bench space needed.
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Product Information


  • Sterile, disposable, 51-well trays.
  • Enumerate bacteria using Colilert®, Colilert®-18, Colisure®, Enterolert® and Pseudalert®.
  • Maximum counting range of 200 per 100 ml without dilution.
  • Most Probable Number (MPN) table enclosed.
    • 100 trays No.WQT100
  • Approved only for use with IDEXX reagents.


  • Sterile, disposable, 97-well trays.
  • Enumerate bacteria using Colilert, Colilert-18, Colisure and Enterolert and Pseudalert.
  • Maximum counting range of 2,419 per 100 ml without dilution.
  • MPN table enclosed. (Requires Quanti-Tray®/2000 Rubber Insert: WQTSRBR-2K.)
    • 100 trays No.WQT-2K
  • Approved only for use with IDEXX reagents.

How Quanti-Tray® works



By dividing the 100 ml sample into 51 wells, Quanti-Tray uses the Standard Method Most Probable Number (MPN) approach to determine the number of bacteria in the original sample. Automation minimises hands-on time and maximises throughput (up to four samples per minute). The relatively large number of wells provides a high counting range (200/100 ml without dilutions) and very tight 95% confidence limits.



IDEXX's Quanti-Tray/2000 is based on the same statistical model as the traditional 15-tube serial dilution. In the serial dilution method, varied amounts of sample are distributed into tubes. Dilution water is then added as necessary to fill the tubes and cover the Durham tubes. With the Quanti-Tray/2000, the sample is automatically divided into the proper portions by the Quanti-Tray® Sealer, without test tubes, Durham tubes, measuring or dilution water. By automatically distributing the sample into 97 wells of two different sizes, Quanti-Tray/2000 yields a counting range of 1–2,419 with a far better 95% confidence limit than a 15-tube serial dilution.


15-Tube Serial Dilution vs. Quanti-Tray/2000


View/Print Quanti-Tray Procedure 

Learn how to use Quanti-Tray




Learn how to use Quanti-Tray/2000






A step-by-step guide to using Quanti-Tray and Quanti-Tray/2000


Step 1

Add sample/reagent to tray.


Step 2

Seal tray in Quanti-Tray® Sealer.


Step 3

Incubate, count positive wells and refer to MPN table.

Quanti-Tray counts from 1-200.


Quanti-Tray/2000 counts from 1-2,419


Frequently asked questions and answers


Are Quanti-Tray and Quanti-Tray/2000 U.S. EPA-approved?

Yes. U.S. Environmental Protection Agency (EPA) has stated in writing that Quanti-Tray and Quanti-Tray/2000 can be used for compliance testing. Quanti-Tray approval letters from U.S. EPA are available on request.


How do Quanti-Tray and Quanti-Tray/2000 compare to other standard methods?

Quanti-Tray provides a wider counting range than and comparable accuracy to membrane filtration (MF).

MethodLower Counting Range/100 mLUpper Counting Range/100 mL
5-Tube MPN
10-Tube MPN
Membrane Filtration


Are Quanti-Tray and Quanti-Tray/2000 trays sterile?

Yes, the trays are gas-sterilized using ethylene oxide. A certificate indicating sterility is included with each box.


What is the shelf life of Quanti-Tray and Quanti-Tray/2000?

The shelf life of Quanti-Tray and Quanti-Tray/2000 is up to 3 years from date of manufacture. When storing opened bags of trays, fold over the opened end of the bag and seal with tape.


Does the temperature of the sealer affect the organisms that may be in the water sample?

No, the short time period that the tray is in the sealer will not harm the bacteria. The temperature in the wells will not increase more than 5°C during sealing.


Sometimes a few of the wells are not completely filled, what impact will that have on interpreting results?

Empty wells do not affect the test interpretation as long as the entire sample is in the tray. The effect on the Most Probable Number (MPN) table is statistically insignificant. An empty or partially filled well is interpreted the same way as a full well.


Can the trays be stacked in the incubator?

Yes. Quanti-Trays can be stacked as high as desired. Use caution not to block the airflow in the incubator.


How is Quanti-Tray interpreted when using Colilert® or Colilert®-18?

Use the Quanti-Tray® Comparator (#WQTC) or Quanti-Tray®/2000 Comparator (#WQT2KC) as a reference. Any color or fluorescence equal to or greater than the comparator is considered positive.


Some Colilert and Colilert-18 positive wells are darker than others. How does this affect interpretation?

Color intensity is a reflection of the different metabolic rates and final concentrations of the coliforms and E. coli in the different wells. Any yellow color or fluorescence in the sample well equal to or greater than the Quanti-Tray or Quanti-Tray/2000 Comparator is considered positive.


How do you interpret fluorescent wells that are not yellow when using Colilert or Colilert-18?

To determine the presence of E. coli, wells must be yellow and fluoresce. A fluorescent well that is not yellow is not an E. coli-positive well.


Quanti-Tray and Quanti-Tray/2000: Everything you need
for confident outcomes


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