Quanti-Tray System

Take the guesswork out of bacterial counts

Quanti-Tray System main image
  • Provides easy, rapid, and accurate bacterial counts.
  • Quanti-Tray and Quanti-Tray/2000 are used when quantifying coliforms, E. coli, enterococci, Pseudomonas aeruginosa, and Heterotrophic Plate Counts (HPC).
  • The Quanti-Tray/Legiolert is only used to quantify Legionella pneumophila.
  • The Quanti-Tray System delivers semiautomated quantification methods based on the Most Probable Number (MPN) model.
  • Learn about the Quanti-Tray Sealer PLUS and our generous trade-in program.
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  • No media preparation.
  • No pipetting.
  • No dilutions (for counts up to 200 with Quanti-Tray; 2,419 with Quanti-Tray/2000).

  • 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.


How Quanti-Tray works


With Quanti-Tray, a 100 mL sample is divided into 51 wells. Then the Most Probable Number (MPN) approach is used to determine the number of bacteria in the original sample. Automation minimises hands-on time and maximises throughput (up to 4 samples per minute). The relatively large number of wells provides a high counting range of 1–200 (without dilutions) and very tight 95% confidence limits.


The Quanti-Tray/2000 is based on the same statistical model as the traditional 15-tube serial dilution. With the Quanti-Tray/2000, the sample is automatically divided into the proper portions when sealed by the Quanti-Tray Sealer PLUS. The Quanti-Tray system does not require the use of test tubes, Durham tubes, or any dilutions. By automatically distributing the sample into 97 wells of 2 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.


With Quanti-Tray/Legiolert, a 100 mL sample is divided into 96 wells. The Standard Methods’ Most Probable Number (MPN) approach is used to determine the number of bacteria in the original sample, using the MPN tables provided. Automation minimizes hands-on time and maximizes throughput (up to four samples per minute). The 96-well tray provides a counting range of 1–2,272 (without dilutions).

Quanti-Tray Sealer PLUS

The Quanti-Tray Sealer PLUS is the next generation sealer in the Quanti-Tray system. The sealer makes quantification with Quanti-Tray and Quanti-Tray/2000 possible while saving time and improving laboratory efficiency. Features include a 2–3 minute warm-up time, faster sealing of trays, energy efficiency, and an access panel that makes cleaning easy.

How to Use

Learn how to use Quanti-Tray

Step-by-step guide to using Quanti-Tray


Step 1

Add sample/reagent to tray.

Step 2

Seal tray in Quanti-Tray Sealer PLUS.

Step 3

Incubate, count positive wells, and refer to appropriate MPN table.


Q & A

Frequently asked questions and answers

How do Quanti-Tray, Quanti-Tray/2000, and Quanti-Tray/Legiolert compare to other standard methods?
Quanti-Tray provides a wider counting range than and comparable accuracy to membrane filtration (MF).

Method Lower Counting Range/100 mL. Upper Counting Range/100 mL.
Quanti-Tray <1 200
Quanti-Tray/2000 <1 2,419
Quanti-Tray/Legiolert <1 2,272
5-Tube MPN <1.1 16
10-Tube MPN <1.1 23
Membrane Filtration <1 80

Are Quanti-Tray, Quanti-Tray/2000 trays sterile?
Quanti-Tray and Quanti-Tray/2000 are gas-sterilised using ethylene oxide.

What is the shelf life of Quanti-Tray, 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?
One or two 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) is statistically insignificant. A 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 up to 10 trays high. Use caution not to block the airflow in the incubator.

How is Quanti-Tray interpreted?
Please refer to the package insert to determine result interpretation.

Some Colilert and Colilert-18 tests positive wells are darker than others. How does this affect interpretation?
Colour intensity is a reflection of the different metabolic rates and final concentrations of the coliforms and E. coli in the different wells. Any yellow colour 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 the Colilert or Colilert-18 tests?
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.

Tests & Accessories

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Resources & Product Information


IDEXX Water has reference materials and approval documents to support the many products in our water portfolio.

IDEXX Water Customer Support

UK Headquarters

IDEXX Technologies Ltd Units 1B & 1C, Newmarket Business Park, Studlands Park Avenue, Newmarket, Suffolk, CB87ER

Tel: 01638 676800


ISO Certifications

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