Quantitative RT-PCR on blood

[P. Mertens]

Among all available methods or kits to obtain RNA (either total or mRNA), 
 what would be the best to obtain starting material for quantitative 
RT-PCR from blood? The available blood quantity will be less than half a 
milliliter.
I'm currently using TRIzol with success to purify RNA from tissue 
samples. Does anyone have comments about the TRIzol-LS for liquid 
samples?
Any comments will be appreciated.
Pascal