Serum Storage and Thawing - Advice needed (Jan/18/2007 )

This is the first time I am working with human serum. I will be using them again and again for next few months and till that time I need to store them.

What are the precautions I should take?

Any word regarding serum storage and thawing will be appreciated.

I used to work with serum, before storeged I added sodium azide (0.1% final conc.) to keep out microbes and as vietello said mantein in a small portions (best if use 1-2mL screwcap microfuge tubes).

Thank U for ur suggestions

I have learned till now about this topic is -

- serum once stored and freezed (we do at -80), can be thawed and refrozen only once.
- so it is better to store them in small aliquots rather than a single (this I did wrong)
- if U r scared about contamination, add azide.

Can someone suggest me how human serum is thawed - what temp, how fast, etc.

What I did was, I put it in 37 deg water bath until it was almost thawed but not completely then let it thaw completely in 4 deg.

Was that good enough??

And, I have kept them after thawing in 4 deg and should be discarding them after a week - am I right?

Please write anythng U know about this topic.

Its not the whole serum you need to be concerned about but the stability of the analytes you are studying. Also, there may be an issue about how soon after collection you freeze the serum. Are you working on lipids, proteins, steriods, inorganic ions or all of these?

I am working with antibodies in human serum.

Treat as protein: keep the samples in ice on the bench when you are using them and avoid freeze thaws. Even the bigger complexes shouldn't break down too much if you are careful. You may get some so called cryoglobulins precipitating out. These are IgM class molecules that pop out of solution below 37C. I'm not sure if they resuspend well on warming. Do you think it would be worthwhile doing a stability experiment to confirm the storage conditions?

Thank U for ur reply. It is really helpful for me.

I am working to detect IgM and IgG class of antibodies and my experiment for IgM worked fine last time. But, if they are precipitating out then I should be careful in interpreting the result I get as I may have lost some while freeze-thawing. I do all my experiments on ice.

I store my serum sample in -80 deg and like I have been told I thaw them by first putting them in 37deg bath and transferring them to 4 deg and letting them thaw completely there.

I am not aware of stability experiment. Is it like comparing titers before and after freeze-thawing?

If there are any literature I can refer to please suggest me.

It is better to thaw at 4C overnight rather than heating them at 37C. If your experiment allows.

i dont know about human serum but i know about FBS and i think they are similar．in lebanon we used to thaw serum on ice,never at room temperature. here in japan we are thawing it at room temperature and they say it is ok.　however, i would never go and thaw at 37! i think that is way too much. good luck! gambatte ne!