PBS Saline for Immucor FMH Screen

[capndave]

I have just received a technical communication from Immucor re the upcoming package insert change for the Fetal Bleed Screening Test requiring the use of "phosphate buffered (approx. 15mM) isotonic saline with a pH of 6.5-7.5". We are small facility and would never use 10L of solution during the typical dating period of 1 month. Does anyone have a suggestion for where we can obtain small volume (100-500mL) containers of this solution or tablets to make it?

[clmergen]

You can buy pHix from Immucor and make up small batches at a time. It just requires pipetting and QCing.

[David Saikin]

I'd like to see their data supporting this change . . . not that they'd mislead me, but I haven't had any discrepant results (that I know of) . . . I use a pH adjusted buffered blood bank saline.

[capndave]

I too would like to see the data. We have not had any discrepant results that we are aware of, but the package insert is the std. It would have been nice when I called Immucor tech support about a source for PBS if they would have offered to sell me some!

[capndave]

I forgot to ask what is the shorthand "pHix"?

Is there a catalog #?

How extensive a QC are we talking about?

Expiration of the original solution and the working solution?

We probably only do 200-250 FMH per year.

Thanks for the help.

[L106]

The name of the product is "pHix", Product # 005070 from Immucor. It comes in a box with 6 plastic bottles with 200 mL in each bottle. You add one 200 mL bottle of pHix to a 20-liter cube of unbuffered isotonic saline. Then you must test the ph and it should be between 6.5-7.5. (We use pH paper to test it, and we never have a problem with the pH being out of acceptable range.) It is then good of 31 days from the date prepared. Contact your Immucor rep for a price quote, but I suspect it will be around $100 for a box.

As clmergen mentioned earlier, you should be able to pipette and measure to make up smaller batches at a time. It would be great if you could share a box (and the cost) with other institutions.

What would be even better would be for Immucor to provide (or sell at a nominal cost.....HA!!!) small quantities since they are saying it is necessary for their FMH kit/procedure.

[BBK710]

I'd like to see their data supporting this change . . . not that they'd mislead me, but I haven't had any discrepant results (that I know of) . . . I use a pH adjusted buffered blood bank saline.

I have not heard from Immucor about this as yet. Are you saying that our regular pH adjusted buffered b lood bank saline can no longer be used for Immucor's fetal screen test?

[clmergen]

They are going to start requiring its use for the Fetal Screen test.

And we haven't seen any problems either. I know that the last CAP Survey had non consensus but it's a screening test. I still have no problems with a false positive Fetal Screen test (again, hemo does the KB stain, so I really don't have room to complain). Now if I were getting False Negatives I would have already jumped on this wagon.

[adiescast]

We use the Phix PBS for our testing and we still got discrepant results ("false positive") on the last CAP survey. I don't buy this solution to the problem.

[tbostock]

I'd never use that quantity in a month; what a waste. I have asked Immucor to provide a smaller quantity of pHix to its customers with each kit...no answer from them yet on that one.

The name of the product is "pHix", Product # 005070 from Immucor. It comes in a box with 6 plastic bottles with 200 mL in each bottle. You add one 200 mL bottle of pHix to a 20-liter cube of unbuffered isotonic saline. Then you must test the ph and it should be between 6.5-7.5. (We use pH paper to test it, and we never have a problem with the pH being out of acceptable range.) It is then good of 31 days from the date prepared. Contact your Immucor rep for a price quote, but I suspect it will be around $100 for a box.

As clmergen mentioned earlier, you should be able to pipette and measure to make up smaller batches at a time. It would be great if you could share a box (and the cost) with other institutions.

What would be even better would be for Immucor to provide (or sell at a nominal cost.....HA!!!) small quantities since they are saying it is necessary for their FMH kit/procedure.

[JoyDenver]

We were notified of a lot recall due to particulate matter in the indicator cells. Immucor is busy restructuring their QA dept. so it will be interesting to see if they come up with a different reason for the false pos's with their FS kit.

[robrien]

I received the notification from Immucor about using buffered saline for the Fetal Blood Screening Test. We also have not had any problems with the test. I have tried to reach their technical support for several days to determine if using the buffered saline will become a mandatory part of their SOP. No answer yet. Does any other manufacturer provide smaller amounts of the buffered saline?

[bjwhite]

They are going to start requiring its use for the Fetal Screen test.

And we haven't seen any problems either. I know that the last CAP Survey had non consensus but it's a screening test. I still have no problems with a false positive Fetal Screen test (again, hemo does the KB stain, so I really don't have room to complain). Now if I were getting False Negatives I would have already jumped on this wagon.

I agree 100%. False positives can easily be tested with the KB Stain. False negatives are another story. We have not seen any false positives either.

[phouck]

I just talked with Immucor about this today and told them that if I could find someone else that manufactured a Fetal Bleed Screening test, I would buy it in a second and leave them behind. We, too, are a small facility and would never use 20L before the expiration date. They told me that they had thought about putting the buffered saline in the kits but that it would not work because of the volume needed. They also told me that it was the small hospitals that were having the problem. We have not had a problem with false positives (Hematology does the KB). I think that it is a bunch of "horse hocky". There has to be a better way to fix the "problem". We use saline with a pH of 6.0 - 7.5 from Thermo. The person at Immucor told me that the pH would drop way below that once the cube was opened. He said that by the time it was 3 weeks old the pH would be 5.0. I am not so sure about that.

I believe that we will use what we have for as long as we can. Of course, when the new package insert comes out, we will have to figure something else out. I feel that it is a shame that we should have to use our financial resources for something that is not our fault or for something for which we do not have a problem.

phouck

[tbostock]

"They told me that they had thought about putting the buffered saline in the kits but that it would not work because of the volume needed."

Huh?? Have they thought about sending it outside the kit? I'm right there with you, phouck. I still believe that they should do the right thing and supply it to their customers...but only they have proven that it is the issue, and have updated their instructions to reflect this.

We should all stand united and put our collective foot down! Oh, sorry, I'm feeling a little tough today.

[bjwhite]

Immuno Concepts makes a PBS powder that you can mix with 1L of sterile water. The PBS comes in a box of 20 powders that are good for a couple of years. Would this not work?

[BBK710]

I just talked with Immucor about this today and told them that if I could find someone else that manufactured a Fetal Bleed Screening test, I would buy it in a second and leave them behind. We, too, are a small facility and would never use 20L before the expiration date. They told me that they had thought about putting the buffered saline in the kits but that it would not work because of the volume needed. They also told me that it was the small hospitals that were having the problem. We have not had a problem with false positives (Hematology does the KB). I think that it is a bunch of "horse hocky". There has to be a better way to fix the "problem". We use saline with a pH of 6.0 - 7.5 from Thermo. The person at Immucor told me that the pH would drop way below that once the cube was opened. He said that by the time it was 3 weeks old the pH would be 5.0. I am not so sure about that.

I believe that we will use what we have for as long as we can. Of course, when the new package insert comes out, we will have to figure something else out. I feel that it is a shame that we should have to use our financial resources for something that is not our fault or for something for which we do not have a problem.

phouck

Just tested a saline cube opened 2 weeks ago. pH is 7.0. So I think that our regular blood bank saline should be fine.

[carolyn swickard]

The Immucor Technical Communication really only states that they recommend "buffered saline", not that it has to be pHix buffered saline. If you switch to buffered saline for all of your Blood Bank work, wouldn't that use it up fast enough? We used Nerl buffered saline (available from Fisher and probably Cardinal) for several years before switching to pHix buffered saline after purchasing an Immucor Echo. All of our BB washing and diluting was in buffered saline and it works just fine.

[capndave]

The thought of re-validating all of our serologic testing with PBS was enough for me to say switching to PBS for everything is a last choice. Sounds like the PHix from Immucor will end up being our resolution- a lot shorter validation process.

[LaraT23]

If you check your Ortho typing reagents, most of then also state that if you don't use buffered saline, some reactions may appear weak. I just switched to a 10L cube and we do throw away quite a lot. By the way I had three false positives last month and if you all will notice the last cap survey included a no score on one item due to lack of participant consensus. That is what got immucor's attention!!

[adiescast]

Just tested a saline cube opened 2 weeks ago. pH is 7.0. So I think that our regular blood bank saline should be fine.

I'm afraid that Immucor is correct. While some opened cubes of saline may maintain their pH, many do not and a pH of 5 is not uncommon in saline cubes (even ones that have not been opened) in the absence of a pH stabilizer. Also, many labs are either unaware of or ignore the manufacturer's recommendation of a month's expiration on opened saline cubes.

[Beverly Morris]

We use Azer Scientific 10L cube disodium phosphate buffered saline ph 7.0-7.2 with 30 day expiration after opening. It maintains the pH range during the opened dating perod. We have a very low false-positive rate, but they still occur. We just had one last week. I do not plan to change to the Immucor reagent saline.

[DBRITT]

We are a small hospital also and have the same issue of not needing 10L. I haven't found anywhere that has smaller bottles. For space reasons I really don't like switching to 10L cubes, but they are cheaper than the 1 gal bottles that we have now. So I guess that's the bright side of the problem.

[Patty]

We just purchased 2.5 gal of buffered saline for the fetal screen test. It is 0.85% Isotonic Solution. The inserts for all our BB testing require 0.85 - 0.90% Isotonic Saline. We will probably just substitute the Buffered saline for all BB testing. Has anyone else done this? What sort of validation is needed if any?

[yolivermagee]

Does Nerl Diagnostics Blood Bank Saline, pH 7.0 TO 7.2 (buffered saline) without additives or preservatives satisfy the Imucor requirement? Cardinal cat. B3158-8