Separate cells from plasma within 2 hours

[docap7]

Is there a reference/ study regarding separation of cells from plasma of blood bank specimens within two hours?

Is this question already been discussed here? 

Thanks.

[Malcolm Needs ☆]

I've never heard of this, and several of our hospitals do not separate the plasma from the cells at all, so that there is no chance of mislabelling of the separated plasma samples.

[Dansket]

I believe it is a "solution looking for a problem".  There is no reason to do this routinely, maybe only when there is an identified problem with a specific patient.

[MAGNUM]

We separate ALL of our samples from the cells. I do not have reasoning for this, just that this is the way it has always been done here and also the way I was trained soooooooooooooo long ago.

[SMILLER]

_{We do not routinely separate plasma from cells either.}

 

_Scott

[cthherbal ☆]

We do not.

[KKidd]

We stopped this practice at least 10 years ago.  The concern was patient identification and mixing up of samples.  It makes life much simpler.

[mollyredone]

Same here.

[AuntiS]

We separate our plasma from cells as well...

But, for those who do separate, what are your policies for how long a sample is good for?  We have a policy for pre-op samples that allows us to use their plasma up to 28 days after collection (no tx or preg in < 3 months), so I'm thinking that they should be separated.

I love the idea of skipping that step, tho....

S

[Abraham]

We only seperate plasma if it is a pre-op specimen that needs to be frozen.

[jojo808]

Maybe it stems from the fact that most specimens for Chemistry testing needs to be separated within 2 hours? Just a thought. 

[aafrin]

We do not separate specimens either.

@jojo808 you are right, i too think that must be the reason.

[Eagle Eye]

We do not

[OneMore]

I have worked in 8 different facilities, and have never separated plasma from cells.  For standard blood banking needs, the samples are fine for the 72 hours the specimen would be utilized.  If reference testing was needed (send-out antibody ID or reaction confirmations), new specimens were drawn for the send-outs.  Only one facility allow pre-op testing to be drawn early, and they had a 7-day limit without separation in order to preserve integrity.  I believe that 7 days is the recommended limit for non-separated tubes before you have interference from degradaion, but I do not have the AABB technical referece for that at the moment.

 

In all honesty, it is rarely impossible for patients to have blood collected in the week prior to surgery.  I like the concept of collecting pre-op samples 48 hours before surgery, as that will allow the blood bank time to resolve most issues and have units available for the scheduled procedure rather than causing a cancellation due to inability to obtain units/resolve discrepancies/identify antibodies before the surgeon starts.  I personally see no reason to be storing samples for 28 days pre-op, and you might really appreciate having the space back!

 

Best of luck!

OneMore

[tbostock]

We also do not separate.

[mcgouc]

In the old days, we used red top clot tubes & were told to use serum so complement would be present. We separated & refrigerated as soon as we finished the testing to preserve the integrity of the sample. Of course we did 15 minute saline room temperature screens & crossmatches in addition to poly specific (again, anti-complement was important) AHG screens & crossmatches. We did have a few ABO discrepancies because we mixed serum tubes. Now, I use anticoagulated samples, don't separate plasma from cells, IgG crossmatches (if we need an antiglobulin xm), and computer xms. I really don't miss the Lewis, P1, etc antibodies.

[Abdulhameed Al-Attas]

We do not.

[dmpollock]

I recommend NOT separating plasma from red cells. All that does is create an opportunity to mislabel the aliquot. I can tell you from having performed about 100 AABB and CAP inspections that the number of blood banks separating the plasma is definitely a minority.

 

I was concerned about stability of our samples for PAT testing, so I made it a project for one of the MT students. I had her take 100 samples, run them on the ECHO on the day of collection, then rerun them on day 21. The comparison was made on ABO/Rh reactions (since I was concerned about using them for immediate spin crossmatch. This was prior to electronic crossmatch.) In 100% of the samples the ABO/Rh matched after storage. By running these on an analyzer it removed bias in the readings.

 

There was a slight drop in strength of the back type, but not enough to cause an ABO front type/back type discrepancy.

 

The specimens evaluated were all EDTA.

 

Of course, the procedure for testing must use samples that meet the specifications in the package inserts for the reagents being used. They typically will give a 7 day limit for testing refrigerated specimens without separating plasma. Be sure to check all the inserts, since the reagent cells might have a different time limit than the antisera.

[Dr. Pepper]

In the old days, we used red top clot tubes & were told to use serum so complement would be present. We separated & refrigerated as soon as we finished the testing to preserve the integrity of the sample. Of course we did 15 minute saline room temperature screens & crossmatches in addition to poly specific (again, anti-complement was important) AHG screens & crossmatches. We did have a few ABO discrepancies because we mixed serum tubes. Now, I use anticoagulated samples, don't separate plasma from cells, IgG crossmatches (if we need an antiglobulin xm), and computer xms. I really don't miss the Lewis, P1, etc antibodies.

We did this because Peter Issitt (and others) told us to. He regretted it in the next Applied Blood Group Serology. In hindsight, it was undoubtedly a conspiracy masterminded by the manufacturers of anti-Lea, anti-P1, anti-M etc.

[MAGNUM]

Is there a AABB reference for this?

[Clarest]

Hi dmpollock,

 

I am wondering why you were only concerned about immediate spin crossmatch. How about full crossmatch for patient with alloantibody(ies)?

Right now, the hospital where I work does plasma separation from cells on all samples. Most of  the samples received in Blood Bank are tested within 24 hours. However, the samples are kept in the fridge for 1 month here if patients have not been transfused or pregnant in the last 3 months. Because of the practice of separation of plasma, before the technologist performs crossmatch on previously separated samples, they need to do a reverse grouping check by testing patient's plasma with A1 and B cells to make sure there is no error during separation. I really do not like this plasma separation practice, but if I want to eliminate it, I have to prove to them there won't be any impact on test results. In the hospital where I previously worked, the maximum time of samples that can be kept in fridge as pre-transfusion samples is 21 days. However, we separate plasma for Pre-admission patients and for those with alloantibodies.

My main concern is that towards the end of one-month period, if the plasma without being separated from cells is still good for crossmatch. I would appreciate any inputs. Thank you.

[tbostock]

Regardless of separation or not, your crossmatch would not be valid at one month.  The best thing to do it to read all of your package inserts for every reagent that you use to do crossmatches.  Most of them give a time limit for testing.

 

And I don't believe there is a reason to separate if you are using EDTA tubes; as a matter of fact it has been shown to increase errors.

[MAGNUM]

We have recently begun not separating the plasma from the cells. We had a mix up that resulted in the patients from that chunk of time that day being recollected and repeated. Since then, no problems.

[Likewine99]

We do not separate.  I have seen 2 instances where the plasma pour off tubes were attached to the wrong tube containing the RBCs.  In one instance one of the pts had a Kell, the other was an ABO discrepancy that was caught thankfully with an ISXM.

[Eoin]

We do - but we have a huge number of pre-op clinics, and this allows us to freeze the plasma for use when they present for op.

All work (including aliquots etc) is checked by a second scientist and signed off on the worksheet as being correct -- and we allow only one specimen to be separated at a time - cumbersome I know, but it works. WBIT doesn't bear thinking about.

Cheers

Eoin