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Recommendations by the Quality Task Group
[18] Bowie Dick Test

Unlike the vacuum test, the Bowie Dick test (steam penetration test) which must be run daily shows not only leaks but also checks the air removal and signals the presence of any non-condensable gases (inadequate air removal manifest as air pockets in the indicator) in the steam. This test must be run daily as per DIN 58946, Part 6, Table 1, before beginning sterilisation. In addition, the manufacturer’s instructions must be observed.

The requirements for chemical indicators used in the daily Bowie Dick test are described in detail in the EN 867 series of standards. Based on EN 867, Part 3, a standard test pack composed of smooth, bleached cotton towels is folded to measure 220 3 300 mm and piled to a height of 250 mm. The resultant weight must be 7 kg w 10 %. A Class B (EN 867, Part 1) indicator sheet is placed in the centre of the pack. The test is conducted at 134 °C with a hold time of 3.5 minutes or at 121 °C with a hold time of 15 minutes (the manufacturers instructions must be observed).

In line with EN 285, the test pack should be placed in the centre of the previously heated autoclave (100 - 200 mm above the chamber floor). The management must be informed immediately if the indicator sheet does not show a uniform change in colour, and this must be documented. The autoclave must immediately be taken out of service if a repeat test also shows irregularities on the indicator sheet because it must then be subjected to technical testing. Having conducted technical testing, the Bowie Dick test must definitely be repeated.

Since February 2001 this matter is regulated by DIN EN 867, Part 4. This standard outlines stipulations for indicators that can be used as an alternative to the Bowie Dick test (standard test pack) for furnishing proof of steam penetration. This standard is of paramount importance for the CSSD as daily functional testing of the steriliser by means of the Bowie Dick test is mainly conducted with alternative indicators.

Alternative indicators constitute an entity of their own and comprise the indicator system (test sheet) and a test load (test packs, helix), which can be for single or repeated use. Here it must be borne in mind that either the manufacturer himself or an external test laboratory must have tested alternative indicators, as per the requirements stipulated in DIN 867, Part 4, for the ability to change colour and to simulate a fault on reaching the temperatures 134° and 121° C.

Only trained specialist personnel may perform the Bowie Dick test. There is no need to preserve the indicator sheet, but it is recommended that the test result is documented by 2 authorised members of staff (e.g. in the sterilisation log). This document should include:

1. Date
2. Autoclave no.
3. Bowie Dick test used
4. Passed/failed
5. Batch no.
6. Signature of the authorised staff member(s)
7. Measures initiated in the event of "failed"

Just as in the case of patient charts, present German regulations decree that results’ documentation be kept for 30 years. (German Civil Code - BGB; limitation period after which compensation claims become statute-barred). Claims from the doctor-patient contract or from the hospital admission contract become statute-barred after 30 years pursuant to Article 195 of the German Civil Code. Because German legislation recognises the principle of shifting the burden of proof, which states that hospitals must prove that no damage was inflicted on the patient, this documentary obligation also applies for the CSSD.