"Promoting the Science of Sterilisation"


gke Steri Record
Batch Monitoring Indicator System


The ethylene oxide monitoring indicator system has been developed to check each batch of the ethylene oxide sterilisation cycle.
The indicator system may be used for pure ethylene oxide under low pressure conditions and also for ethylene oxide CO2 or inert gas mixtures under pressure.

EtO/l (mg) Pressure (bar) CO2(%) CO2(%) Time (min)
500 1.7 85 15 90
600 5.5 94 6 60
250 1.7 94 6 180
1200 5.5 85 85 30
600 0.2 0 100 60

During the sterilisation process it is absolutely necessary to monitor the relative humidity, which should be above 50% and never drop below 30%.

The attached process challenge device (PCD) which has a connected Teflon tube of 1.5m length simulates worst case penetration conditions.
If a sterilisation cycle without pressure differences is used the penetration of ethylene oxide in the PCD may be too difficult. If so remove the Teflon tubing from the metal holder or place the indicator in sever sterilisation bags to simulate worse case penetration conditions.

Sterilisation programs are not standardised. Therefore a validation with b. subtilis bio-indicators is required before the chemical indicator can be used for routine sterilisation monitoring.

gke produces Steri-Record® bio-indicators b.subtilis 106 for ethylene oxide sterilisation processes on paper strips or self contained Bio-Pus indicators.

Directions for Use

1.As described above, select the right package depending on your sterilisation cycle and validate the process with bio-indicators. Always use the same sterilisation cycle and the same chemical indicator packing procedure during each validation and routine monitoring run.

2.Insert the indicator strip in sterilisaton bags or the enclosed PCD. Fold the indicator strip in the middle and place it in the test device with an opening towards the tubing inlet. Make sure that the washer is in perfect condition and close the cap.

3.Place test system including indicator between sterilisation goods and place one unprotected indicator as a reference in the chamber close to the bottom and near the door. Start the sterilisation program.

4.After the ethylene oxide extraction stage remove the indicator from the test system and check the result against the reference indicator or reference chart.

5.All four indicator bars on the strip must change colour from blue to green. Use the unprotected indicator strip as a reference.

6.Release the sterilisation batch depending on colour result and attach the indicator strip (which is self adheseive) to the documentation page.

Documentation Information
  • Stick all batch monitoring strips from the one day to the documentation page.
  • To ensure traceability from batch monitoring to sterilised goods gke offers a label print device (L230-850). These labels include date of production, expiry date, not number and user. They are placed on all sterile packaging and also on the documentation page. After use of the sterile goods in the operating room, the labels (which are double self adhesive) are removed and finally placed in the patient's file. this simple process offers inexpensive and effective documentation of all sterilised goods used on each individual patient.
Important Considerations
  • The colour monitoring indicator and test device are optimised in terms of inner volume and chemical composition. gke will not guarantee the results of the monitoring system if other indicators or PCD checking devices are used.
  • It is absolutely necessary that the relative humidity appearing during the validation process will also appear during all sterilisation cycles.
  • The batch monitoring with chemical indicators is no replacement for regular tests with bio-indicators. The sterilisation process must be validated with biological indicators before start up, after repair and after a certain amount of sterilisation cycles, determined by your local requirements.
  • If other sterilisation programs are used a new validation procedure with biological indicators is required.
  • If other ethylene oxide cartridges are used, revalidation is required.
  • Indicators need to be stored below 25°C and 70% relative humidity. Do not store them together with other chemicals as the vapour of chemicals may destroy the indicator.
  • Do not use indicators after the expiry date. Refuse can occur with the normal garbage.
  • The metal test device, if used, should be checked for leakage. Additional washers are available in refill packs.
  • If the device or Teflon coil is damaged immediate replacement is required.
  • Please contact us if technical assistance is required.
Download our PDF on Manufacturers Directions for Use