Freeze means: lower portion (4C) or upper chamber (-20).??

I will prefer to freeze at -20 or -80, then it is good for long time, for months. But at 4C, I will not keep for more than a day or two and then aliquot and freeze them.

Hello Marwan Y. Al-Maqtoofi

Preferably the analysis should be done immediately, or store samples at 4°C (up to 48 hours), -20°C (up to one month) or -80°C (up to two months). As far as possible avoid freeze-thaw cycles. Bring the samples to room temperature before carrying out ELISA.

Best.

It depends on the stability of the analyte, so it's difficult to give a figure. If possible, freeze reference samples (e.g., spiked serum) and, if you have a bigger project, include testing for sample stability.

Store your materials as cold as possible and in aliquots, to avoid repeated freeze-thawing, which affects protein stability.

Thanks for all

They were kept at -80C right now.

Thanks again.

There is experience to store aliquoted sera at -80*C for years.