Question

Kelly is crime scene investigator. She is examining a stain that she suspects is blood. Presumptive tests indicate blood, so she is choosing which
confirmatory test to use. What are the disadvantages of confirmatory tests?
Kelly considers using the
test to confirm whether the stain is blood; however, she knows that it could be unreliable
because the stain is on a leather boot. Kelly considers using the
test, but she believes the stain may be about 35 years
old, and this test is not as reliable for stains over 20 years.

Answer 1

Confirmatory Tests vary, and may be wrong from time to time. As time passes, the test is not as reliable as stated. If the so called "blood" is on a leather surface, blood isn't too prone to sticking to leather, so it may (or may not) be blood.