Blood Storage for DNA Extraction

[Rick Bright]

I have been successfully extractin DNA from frozen blood (-70C) but
today, for some reason, nothing worked out.  The blood was all collected
in the second week of November.  While it was fresher, it had a great,
pure yield.  Now, just garbage, after about 5-6 weeks of storage.

Does anyone know the length of stability for frozen blood for DNA
extraction.  I have obviously crossed the line, but just how far?  Guess
I will have to roll up my sleeves again tomorrow.

Rick
rbright at mnw.net