Thanks for the links, Andrei! Incidentally, I still remember "cooking" Piotr Chomczynski's original recipe in the lab after it was first published :-)

Interestingly, Chomczynski et al do not quote yields from plasma/serum, just mention that the kit is useful for the extraction.

Table 1 is for whole blood - which is really impressive recovery. No mention of plasma or serum, unless I am going totally senile?

I agree regarding BD being the next big thing...

The improvements introduced in later-day commercial TriZol are indeed unknown, but the original (semi hand-written) recipe I have is adapted from Chomczynski and Sacchi Anal Biochem. (1987) and P. Chomczynski et al., Cinna/Biotecx Bulletin #1 (1988).

Nothing like a spell of nostalgia :-)

Checking the actual amount of total RNA from plasma or serum is technically challenging because available protocols to date use exogenous RNAs (like MS2 RNA or yeast tRNA) as carrier RNA to enhance subsequent precipitation and hence, to increase the final yield. The problem with non-RNA "carriers" like PEG is that they can affect downstream applications, i.e. inhibition of qPCR. (Linear polyacrylamides- LPA have been used as carrier but I don't know how it affects other apps). I guess one needs to do two preps using RNA and non-RNA carriers if you really want to know the actual concentration of RNA in a particular serum/plasma sample, and at the same time be able to do downstream applications without worries. Spike in RNAs by the way can also be added to evaluate extraction efficiencies in different samples.

Thanks Jonathan. It's a valid point to double check when reading publications.

I personally think that the practice of adding RNA carrier to RNA extraction is a bad one, and I have been using either linear acrylamide or glycogen successfully for many years - not with serum, but with low numbers of cells.

A