DNA from old blood samples???

Carlo zanon-carlo at netanday.it
Mon Nov 2 01:38:03 EST 1998

VWSAI at AOL.COM ha scritto nel messaggio ...
>After visiting numerous sites I remain unable to answer this important
>question regarding DNA testing and its accuracy- - For what amount of time
>would a blood sample be viable enough for use in a test of identification?
>(almost done)
>and... If that sample were on an article of clothing, and that article of
>clothing was to be washed, would the test results be invalidated?
>..OK, two important questions but important none the less.
>I would really appreciate if somehow you could help me with this information
>Thank you!

In my experience the time was not a limitation in obtaining viable results from
DNA testing (let say months, maybe years).
Much more important are the state of conservation of the organic samples. DNA
exposed to high temperatures or dump environments may be irreparably degraded,
otherwise dried stains of blood usually are good source of genetic material.
As for washed clothes there are works that show the possibility of obtaining
good results: it is not unusual to find such samples in forensic caseworks. In
these cases it is better to test the results repeating the analysis a second or
a third time.

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