Removing serum from cells

[GWBush]

GW thinks that separating serum/plasma from the original tube has the potential to cause major problems.

[lgabbert]

Our pipette does not reach the bottom of the pink tube, so when the crit is low, the plasma must be removed also remove the cells in order to pipette them. How do others handle this?

[L106]

Personally, when I receive a patient's sample in BB, I prefer to transfer a few drops of whole blood into a tube properly labeled with the patient's name before I put the patient's sample into the centrifuge to spin.

[NedB]

I vote don't separate, ever. A Beral Transfer pipet will reach the bottom of any tube. Very gently squeeze the bulb before inserting the open tip to the bottom, release the squeeze and you'll draw up enough red cells to make your 3% or 0.8% cells suspension. It takes practice, but you can do this without mixing red cells into the plasma fraction. We use EDTA - so complement is also a moot issue. The greatly increased sensitivity of the gel and solid phase make up for any shortcomings in use of EDTA.

[eric1980]

I do not encourage separating too. Any convenience is not worth the risk of mix-up or transcription error when labelling the new tube.

[heathervaught]

Our Reference Lab separates the RBC/Plasma or RBC/Serum for all incoming samples. They use a serofuge with the capability to hold 6 x 7 mL tubes, so they spin one patient at a time. Usually one tech works on one case from start to finish, then rubber-bands all of the prepared samples (including any eluates, cell suspensions, cell separations, etc.) together and stores them until the end of the retention period.

[Malcolm Needs ☆]

Our Reference Lab separates the RBC/Plasma or RBC/Serum for all incoming samples. They use a serofuge with the capability to hold 6 x 7 mL tubes, so they spin one patient at a time. Usually one tech works on one case from start to finish, then rubber-bands all of the prepared samples (including any eluates, cell suspensions, cell separations, etc.) together and stores them until the end of the retention period.

We do the separation of the plasma/serum from the red cells for each sample separately, but there is no way that we could work on the actual samples from start to finish separately.

We have about 25-30 samples a day, many of which require complex serology, adsorptions (either auto or allo), titrations or quantitation, cross-matching and many of these take more than 5 hours to complete. With a total bench staff of 9, plus vital help from Assistants and Clerks, we just could not cope working on one sample at a time.

If only we could, life would be so much easier (and safer for the patients).

[macarton]

We don't separate ours. There is an FDA reg that the ABS needs to be done within 48 hrs, so we won't use specimens being held for possible testing beyond that.

[Abdulhameed Al-Attas]

Yes,Mr.Melcolm,you are absolutely right, pipetting off a sample of packed red cells through the plasma is safer,

We have been doing that since we switch Dia Med (Gel Micro typing system),with NO broblems

at all.

Edited October 17, 2009 by Abdulhameed Al-Attas

[Mary**]

Can you give me more details about that FDA reg?

[skopti]

Our samples are collected in Pink tubes. We do not separate the cells from the plasma.

[mwilde]

There was a huge amount of validation performed before the switch from serum to plasma, particularly in the 1990-2000, although, needless to say, I can't put my hands on any of the work just at this moment.

Although it is now a little "elderly", it could be worth your while reading pages 132-133 and page 1182 of the tome by Peter Issitt and Dave Anstee, Applied Blood Group Serology, 4th edition.

Malcolm,

This is an aside to the question about validating serum vs plasma for blood bank testing. Do you or anyone else on BB Talks know where I can acquire a copy of this book? I've looked around on the internet to no avail.

Thanks!

[Malcolm Needs ☆]

Malcolm,

This is an aside to the question about validating serum vs plasma for blood bank testing. Do you or anyone else on BB Talks know where I can acquire a copy of this book? I've looked around on the internet to no avail.

Thanks!

I don't I'm afraid.

I know that one used to have to order them directly from Montgomery Scientific Publications.

[mwilde]

Thanks, Malcolm. I couldn't afford to order one from Montgomery at the time and thought they would be available indefinitely. Unfortunately, they are out of print currently.

Again, anyone on BBTalk who knows of a source, I'd love to get my hands on one!

Thanks!

[Malcolm Needs ☆]

Sorry, I've had a look on the internet in the UK, and I can't find any either.

[mwilde]

Sorry, I've had a look on the internet in the UK, and I can't find any either.

I looked for it on US eBay and Amazon with no success. I may look on some of the international eBay sites. Did you check there in UK? I also have an open request for a copy on Amazon.

Thanks again!

P.S. Do you think Peter would give up his if I contacted him in NC? LOL!

[Malcolm Needs ☆]

Hmmm, I have my doubts.

[Mabel Adams]

Switch to the electronic crossmatch and the issue of the sample remaining in the tube is moot in most cases. We don't separate our plasma unless we are doing antibody ID and that is more for convenience to get access to the pt. cells easily. Then labeling of the pour-off is, of course, critical.

Even if the patient has been transfused, you would be doing a cold autoadsorption--not impossible for there to be some new IgM alloantibody that gets adsorbed but of all the places that have been doing this for more than 10 years have any of you ever had a problem due to this?

Yes, validate use of plasma by running parallel tests known positive and negative samples. There are both K2 EDTA and K3 EDTA tubes so you can validate them both to be sure, especially if you get samples sent in from elsewhere.

[Mabel Adams]

Sorry my previous post is mostly in regard to page one posts so is sort of out of sequence.

I thought the FDA finally got their regs up to the 72 hour std--although it was out of synch with practice for many years.

Edited October 28, 2009 by Mabel Adams
premature posting of half-finished sentence.

[bbbirder]

Yes, Mabel is right that the FDA regs now allow testing up to 72 hours.

Also, we used to separate our specimens, but storage racks were getting to crowded, and we now have an Echo. We don't separate and have no problems.

Linda Frederick

[Yanxia]

I don't think use EDTA anti-coagulate plasma in bloodbank is safe,because EDTA can interference complement depending antibodies detection.

And a question: Why store the blood sample can adsorb alloantibodies in recent transfused patient? In my understanding, the transfused blood can bind the alloantibodies in blood stream, and after be drawn, the antibodies that is not been adsorbed will keep the same state.