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.