DART test in autoclaves: what it is and what it is used for
— Equipo JP Selecta
The DART test checks air removal and steam penetration in pre-vacuum sterilisers.
It is carried out before processing loads in order to detect conditions that could prevent the steam from coming into contact with the material.
A satisfactory result supports the performance of the system under the test conditions; on its own, it does not demonstrate the sterility of subsequent loads.
What is the DART test (Daily Air Removal Test)?
DART is the STERIS trade name for the Daily Air Removal Test, that is, a daily test of air removal. It is a challenge device with a type 2 chemical indicator intended for a specific test. It makes it possible to detect residual air that can impair steam penetration.
It is related to the Bowie-Dick test, but its selection depends on the instructions for the device, the steriliser and the facility's approved procedure. Working under US requirements does not, in itself, make it mandatory to use this brand.
What is the procedure for the DART test?
The test must be performed following the instructions for the DART used and for the autoclave. The procedure combines preparing the unit, exposing the device and reading the indicator; changing the time, position or temperature can invalidate the result.
- Check the identification, expiry date, integrity and storage conditions of the device.
- Prepare the chamber without a production load and carry out the warm-up specified by the manufacturer.
- Place the test at the point indicated in the instructions, which is not necessarily the geometric centre of the chamber.
- Select a compatible cycle for the temperature and exposure time of the device. Do not extend the exposure to obtain a favourable colour change.
- Wait for the cycle to finish and remove the device using the appropriate heat protection measures.
- Read the indicator using the manufacturer's guide. An incomplete or uneven colour change, or one outside the acceptable pattern, requires the incident to be investigated.
- Record the result, the device batch, the unit, the cycle and the person responsible. In the event of a failure, suspend use of the affected cycles until the problem has been resolved and their performance verified.
When should the DART test be carried out?
The air removal test is usually carried out at the start of each working day on which the pre-vacuum steriliser is used, before the first load. The specific frequency must be set out in the laboratory's procedure, in accordance with the unit's instructions and the applicable requirements.
After any intervention that may affect the vacuum, the steam supply or tightness, the planned checks must be carried out before returning the unit to service. A satisfactory repeat test does not erase the previous result: both records and the investigation must be kept to explain what happened and which measure resolved it.
You may be interested in: The autoclave sterilisation process
Differences between the Bowie-Dick test and the DART test
Bowie-Dick designates an air removal and steam penetration test using a challenge load or device.
DART is a commercial solution for that purpose. The difference is not simply a split between Europe and the United States: different devices and conditions of use exist within each market.
Both provide information on the system's ability to remove air and allow the steam to reach the challenge. Neither replaces the leak test or the physical, chemical and biological controls defined for the process. Nor should they be interpreted as direct proof of microbial kill in the actual load processed.
| Criterion | Bowie-Dick test | DART test |
|---|---|---|
| Full name | Bowie & Dick test | Daily Air Removal Test |
| Commonly cited standard | EN 285 / EN ISO 11140-3 (standard pack); EN ISO 11140-4 (alternative device) | ANSI/AAMI/ISO 11140-4 |
| ISO classification | Type 2 indicator | Type 2 indicator |
| Test device | Standard textile pack or disposable device | Compact disposable device (STERIS DART®) |
| Cycle temperature and time | 134 °C / 3.5 min | 132–134 °C / 3.5–4 min |
| Chamber during the test | Empty | Empty |
| Reading the result | Uniform colour change on indicator sheet | Uniform colour change on internal indicator |
| Does it demonstrate sterility? | No. Indicates process conditions | No. Indicates process conditions |
Are these tests interchangeable?
They can only replace one another within a procedure when the alternative device is suitable for the steriliser, meets the relevant requirements and is used with an authorised cycle.
Nominal agreement of temperature and time is not enough to demonstrate equivalence. The person responsible for the process must document the selection and update the procedure whenever the test system changes.
Autoclaves with a Bowie-Dick test and vacuum test programme
At J.P. Selecta we offer the Autester ST DRY USB-S 50, Autester ST DRY USB-S 80 and Autester ST DRY USB-S 150, as well as the Autester ST DRY GMP-S 50, Autester ST DRY GMP-S 80 and Autester ST DRY GMP-S 150, with fractionated vacuum air removal, plus vacuum check and Bowie-Dick functions. We also offer the Autester ST DRY PV-B Print 23L, with a capacity of 23 litres, whose programming includes vacuum and Bowie-Dick tests.
Having a Bowie-Dick cycle makes it easier to perform the corresponding test with the appropriate consumable, but it does not automatically confirm compatibility with every DART. Before use, it must be verified that the device instructions accept the unit and the actual programme conditions. Having the programme does not mean that the test indicators are supplied either.
Cycle logging and test documentation
Our Autester ST DRY USB-S and GMP-S record data from more than 500 sterilisation cycles and include a menu for data transfer via FTP. This information makes it easier to document the tests and relate them to qualification and maintenance activities. The 23-litre PV-B Print incorporates a built-in printer and a USB connection for storing parameters.
The cycle record and the indicator result are different pieces of evidence: the autoclave records the variables it controls; the indicator reading must be added to the file together with its identification. An automatic report must not be presented as a certificate of sterility or as an automatic reading of the DART.
In GMP environments, traceability also requires procedures, responsibilities, review of results and data integrity controls appropriate to the system implemented. Electronic signatures and compliance with 21 CFR Part 11 must be verified in the specific configuration; they cannot be inferred from having a USB connection or from exporting records.
Browse our catalogue of laboratory autoclaves.