Hi Abouzar,

Try use some commercial available kits such as Qiagen / Exiqon

https://www.qiagen.com/my/products/catalog/sample-technologies/rna-sample-technologies/

http://www.exiqon.com/rna-isolation

Thank you

Regards

The mRNA will be degraded typically averaging in the 150-200 base range as measured on a Agilent Bioanalyzer with low RIN values but longer transcripts can and will be present as detectable by RT-PCR. Many groups including ours have successfully performed small RNAseq on serum RNA. The following paper has comparison for different isolation kits. Burgos et. al. 'Identification of extracellular miRNA in human cerebrospinal fluid by next-generation sequencing.' RNA 22Mar2013 From 200 uL serum I've seen 10-50 ng of RNA; however, I was looking specifically at the small RNA expression. I just saw that Qiagen released a kit for exosome and extracellular vesicle isolation but I haven't evaluated it yet; their marketing data makes it sound like a useful tool but will reserve endorsement until I can compare it to other methods.  https://www.qiagen.com/us/products/catalog/sample-technologies/dna-sample-technologies/genomic-dna/exorneasy-serum-plasma-kits#resources

Jeffrey Shelton

Please share your feedback on that kit when you will get results.

Best regards

Thank you very much, I want to do small RNA seq too, but for small RNA seq total RNA have to be qualified, is that true? our 260/280 = 1.8 and 260/230 = 0.5 and there isnt any 28S or 18S on the gel electrophoresis.

it will be qualified for small RNA seq? 

Thank You

Regards

Not sure what you mean by qualified but if you're sending your RNA out for target prep and sequencing then discuss with the company who will conduct the sequencing run; they'll likely have recommendations and provide guidance.

I test by the recovered RNA by real-time PCR for a handful small RNA and miRNA.

Thank you very much.