Making Own Buffered Saline

[AB123]

Does anyone make there own buffered saline? we have just switched to using the Ortho Vision and our local Vendor recommended normal saline not buffered. I have previously used the Vision in the UK and we were always advised to use PBS Ph7.2 and always did, so I was surprised by this advice. Since starting to use the Vision we have noticed a significant number of Cord blood samples with strong Pos DAT and Ctrl well positive, and C3 when checked with the Mono DAT card. When I asked the vendor regarding this he told me this was normal and to be expected, however I told him I don't believe it is as in my 2 previous years of using it I had never had a single case of this. 

I requested they contact Ortho regarding the issue and they came back with checking saline Quality/Ph! The Ph of our normal saline is 4-7 not within specification, the issue I have is that the only PBS I can get hold of here is for molecular biology use and around $100 a liter, as we are using about 150L a month this is not feasible. The ingredients to make PBS are cheap and its easy, or alternately we can just make the buffer to add to the saline.  My concern is about QC and if we will have any issues from CAP/ISO,AABB etc. 

Just wondered if anyone else is doing this and if they have had any issues? Alternately I see Immucor make a product call Phix, that can be added to saline as a buffer, although more expensive this would be far cheaper than the PBS. does anyone use this product and have any feedback? 

There is also a powdered PBS product from a company called RPI which is the right specification and cost effective however they state that its a research product only, has anyone ever use this? 

Thanks 

[mcgouc]

Before getting an ECHO and using the pHix recommended for that, I did buffer the saline using a powder. It was several years ago but I think I got it from Hemobioscience.  I started because some (Immucor) manufacturer’s directions specified a saline pH around 7. Our unbuffered saline did not always meet that pH. We checked and documented pH daily and when we made a batch. We also had standards to check the pH paper daily.  We QC’ed the saline daily as before.  We continued the pH checks after switching to pHix.  

[AB123]

50 minutes ago, mcgouc said:

We QC’ed the saline daily as before.  We continued the pH checks after switching to pHix.  

Thanks for reply

How do you find the pHix? What Ph does it give? and do you ever have to adjust it? ? 

[AMcCord]

pHix is supposed to be guaranteed to maintain a pH of 6.9 to 7.2 for a month. Our saline never lasts that long, so no worries there. We are using pHix buffered saline on the Echo, as recommended by Immucor.

Whatever you choose to do you would need to do validation testing for your method(s) of course, in addition to whatever you do for saline QC.