What is a Bowie-Dick Test and How to Select the Correct Type Test for Your Sterilizer

Understanding the Bowie-Dick Test

The Bowie-Dick test, originally developed in the 1960s, functions as a type test rather than a sterility test. Its primary purpose is to verify sufficient air removal and steam penetration capabilities within the sterilizer chamber. The test operates on a simple principle: if steam cannot penetrate effectively due to residual air pockets or non-condensable gases, sterilization cannot be achieved.

Originally, this test required a 7-kilogram cotton pack with an indicator sheet placed inside. However, modern practice has largely replaced this labor-intensive approach with Bowie-Dick Simulation (BDS) tests, which offer identical or superior sensitivity while providing reproducible results and user-friendly operation.

Standards and Requirements

Different sterilizer types require specific test protocols:

• Large Sterilizers (EN 285): The European standard mandates both the traditional Bowie-Dick test and an additional hollow load test using a helix Process Challenge Device (PCD). This dual requirement emerged after research demonstrated that porous tests alone cannot reliably detect failures in hollow instruments, where less than 1 ml of non-condensable gas can block steam penetration.
• Small Table-top Sterilizers (EN 13060): These systems typically use hollow load tests as their primary type test, though many manufacturers include Bowie-Dick test programs requiring appropriate morning test runs.

Types of BDS Tests Available

Modern BDS systems offer three primary variants, each designed for specific sterilizer programs and standards:

• European BD-Test: Validated according to EN ISO 11140-1 + 4, referencing the 7-kilogram test pack requirements in EN 285. This version addresses both air removal and steam penetration testing.
• American BD-Test: Designed for AAMI/ANSI ST79 compliance with 4-kilogram test pack specifications, validated according to ISO 11140-1 + 5 test methods.
• Hollow Load Test: Following EN ISO 11140-6 requirements (previously EN 867-5), this test serves as an additional type test mandated by EN 285 for large sterilizers.

Selecting the Correct Test System

The selection process depends on your sterilizer's specific BD-test program and applicable standards. Multi-functional systems like the GKE Compact-PCD combine multiple test requirements in a single device, offering both European BD-test and hollow load test capabilities.

When choosing a BDS test system, consider these factors:

• Your sterilizer's specific test cycle requirements (132-137°C or 121°C programs)
• Applicable regulatory standards (EN 285, EN 13060, AAMI/ANSI ST79)
• The types of instruments typically processed (porous loads vs. hollow instruments)
• Operational efficiency preferences

Proper Placement and Operation

Effective test results require proper placement within the sterilizer chamber. Position the test device in the lower section near the door, where non-condensable gases typically concentrate due to their higher specific weight compared to steam. Avoid placement directly on the chamber floor; instead, position the device 2-5 cm above on a tray or rack to prevent drainage in condensate.

Limitations and Considerations

While BDS tests provide valuable functional verification, they represent only one component of a comprehensive sterilization monitoring program. These tests cannot replace routine monitoring with batch monitoring systems or process indicators in individual packages. Additionally, successful morning test results do not guarantee effective sterilization of subsequent loads, particularly for challenging items like hollow instruments.

The effectiveness of any BDS test depends on proper selection, placement, and interpretation. Users should understand that these tests verify sterilizer function rather than load sterilization, making them an essential but not sufficient component of sterilization quality assurance.

Understanding and properly implementing Bowie-Dick testing ensures your sterilization processes meet required standards while maintaining the safety and effectiveness of your infection control protocols.

Partner with Mesa Labs/GKE for Reliable Testing Solutions

Mesa Labs/Mesa Germany, through its GKE brand, offers comprehensive BDS testing solutions designed to meet the diverse needs of healthcare facilities worldwide. With decades of expertise in sterilization monitoring, Mesa provides innovative Compact-PCD systems that combine multiple test requirements in single, user-friendly devices.

Our commitment extends beyond product supply to include technical support, validation documentation, and ongoing consultation to ensure your sterilization monitoring program achieves optimal results. Whether you're implementing new protocols or upgrading existing systems, partnering with Mesa Labs/GKE ensures access to cutting-edge technology backed by proven scientific expertise and regulatory compliance.