There are many options in market for RNA extraction. In our setting, we have used

RNeasy Mini Kit , and Nucleospin RNA kit of MN, as well as manual trizol method and all methods worked well.

I have used Qiagen RNeasy mini kits to Isolate viral RNA from liver tissue and the reults have been very good.. alternatively, I have also used Trisure from Bioline in combination with DNA-free™ DNA Removal Kit from invitrogen.. also while working with a team in Australia, We used Trizol method to extract RNA from Culture cells. This method is much easy and cost effective plus it gives sufficient amount of RNA for gene expression study of culture cells.

There are many options. If you are still collecting your sample it is better to make extraction as soon as possible with no freezing before. You can use QIAamp RNA Blood Mini Kit.

If you need to store the sample for a while, it is better to use RNA later or RiboPure™-Blood with RNAlater®. OR PAXgene Blood RNA Kit IVD

Generally, Be sure that the kit used is matching with blood sample with anticoagulant.

Extract from a fresh sample as long as you can.

Do not allow the sample to be freezed or lysed without addition of RNA later or a reagent saves your RNA

Try to measure RNA after extraction.

Triazole reagents also can be used but also working on fresh sample is necessary.

There are many options in market for RNA extraction. In our setting, we have used

RNeasy Mini Kit , and Nucleospin RNA kit of MN, as well as manual trizol method and all methods worked well.