Are any units using an interim count or different test to obtain an 'early warning' of ring return/RO contamination in addition to the standard R2A, 7 day, 17-23deg method?
We have tried a 5 day 100ml filtration test though currently the results will return a >100cfu/100ml for anything over 1cfu/ml which, though useful to gauge compliance for ultrapure quality, doesn't shed much light on if the sample meets the basic standard for water for dialysis.
If any other unit has had success in using another method as an early warning before the 7 day test is complete I'll see if I can request that from our labs
Have you got further filtration on your machines? If so that should give you the safety net to wait the 7 days for your result and also give you time to take any actions required - or have I just totally missed the point of your question?
We do not have filtration on all of our equipment though they are being replaced with such as they are life cycled. Even with filtration our policy would be to advise against HDF treatments until corrective measures and a satisfactory sample had be completed.
If the standards say:
Dialysis water containing a total viable microbial count of less than 100 CFU/ml and an endotoxin concentration of less than 0.25 EU/ml is also the starting point in the production of ultrapure dialysis fluid or for on line infusion fluid used in haemodiafiltration (HDF). The production of ultrapure dialysis fluid is generally achieved by the use of additional filters which form part of the dialysis machine hydraulic pathway. BS EN ISO 23500:2015 states there is no requirement to test for bacterial growth or endotoxins when the haemodialysis system is fitted with endotoxin retentive filters that are operated according to the manufacturer’s instructions, unless the manufacturer requires such tests to be performed
We recommend that the quality of water produced by the water treatment system shall meet the concentration limits for microbiological contaminants detailed in BS EN ISO 13959:2015. This states that dialysis water shall contain a total viable microbial count of less than 100 CFU/ml and an endotoxin concentration of less than 0.25 EU/ml. If routine monitoring demonstrates microbiological
contaminant levels in excess of 50% of the maximum permitted levels (based on the analysis of historic data) a programme of corrective measures should be commenced immediately.
are you finding yourself outside of these figures? I'm just trying to gauge whether you may be worrying unnecessarily?
Happy with the standards. This query originates from us receiving a very poor result from the labs. No previous trend or breach of action levels so most likely sampling or lab contamination. It really was just to gauge if others use an additional shorter 'non standard' test to give a heads up of an impending poor 7 day count.
Post endotoxin filters on equipment still give 0 counts, as expected, so no worries there
I notice that the latest revision of iso 23500-3 2019 now includes use of Tryptic Soy Agar (TSA) as a recommended method of monitoring microbial burden in water used for conventional or standard dialysis. With the only a 2 day incubation time have any other units moved to this method?
Slightly confused by the explanatory text that mentions a statistical difference between TGEA and TSA and then goes onto to state that working group will include as recommended method for indicating microbial burden in water and dialysis fluid.