I need to extract total RNA from frozen whole blood samples in order to perform Real-time RT-PCR. Does anyone know which is the best kit to obtain high purity RNA suitable for this purpose? The samples are stored in EDTA tubes at -80ºC.
I do agree that QIAGEN kits are top notch, but I reckon the protocol for RNA extraction using QIAGEN kits from frozen whole blood is rather different than the conventional RNA extraction from fresh blood samples. You might want to treat your frozen blood sample with QIAzol until the sample thaws and comes into contact with QIAzol before proceeding with the RNeasy Lipid Tissue protocol (https://www.qiagen.com/us/shop/sample-technologies/rna/total-rna/rneasy-lipid-tissue-mini-kit) as recommended by suppliers.