Different Types of Tests (Exam 1)

Question 1

What 3 types of tests are available to study body fluids?

Answer 1

1) Presumptive
2) Confirmatory
3) Species specificity

Question 2

Is a presumptive test more or less sensitive than a confirmatory test?

Answer 2

More

Question 3

What does a positive presumptive test indicate?

Answer 3

The possible presence of a body fluid in question

Question 4

Can the presence of a stain be confirmed for certain by a presumptive test?

Answer 4

No

Question 5

What happens if a presumptive test is negative?

Answer 5

Testing ends there as no substance of interest was found

Question 6

What are the two types of presumptive tests?

Answer 6

1) Catalytic color
2) Chemiluminescence & fluorescence

Question 7

What are the 2 most common catalytic color presumptive tests?

Answer 7

1) Phenolphthalein
2) Hemastix test strips

Question 8

What is the key reagent in the Hemastix test strip?

Answer 8

Tetramethylbenzidine (TMB)

Question 9

What are the 3 common fluorescence presumptive tests?

Answer 9

1) Alternate light source (ALS)
2) Luminol
3) Fluorescein

Question 10

When should alternate light source be used?

Answer 10

For substances not visible to the naked eye

Question 11

In what 2 ways are the chemiluminescence and fluorescence tests similar?

Answer 11

1) Used when blood is invisible i.e. faded/washed
2) Used when blood is in unconventional spot

Question 12

What does a confirmatory test prove?

Answer 12

The presence of a particular body fluid in a questioned item

Question 13

What does it mean if a confirmatory test is negative given that the presumptive test is positive?

Answer 13

There could be a false negative, especially when considering that confirmatory tests are not as sensitive as presumptive tests

Question 14

What 2 things does a species specificity test prove?

Answer 14

The presence of a body fluid in a stain and what species it belongs to

Question 15

Why could you possibly skip a species specificity test?

Answer 15

You might not have a lot of DNA

Question 16

How do you determine if your sample is human when using a species specificity test?

Answer 16

Use the standard human DNA quantity, and if none of that comes back as human, then none of it is human

Question 17

Blood & semen use the three types of serology tests, but saliva uses…

Answer 17

Salivary amylase enzyme

Question 18

Is estimating the salivary amylase enzyme useful?

Answer 18

It isn’t common but MAY come in handy

Question 19

In what 2 ways are the chemiluminescence and fluorescence tests different?

Answer 19

1) Fluorescence rxn lasts longer
2) Light is a natural product of chemiluminescence

Question 20

What 2 aspects are blood group testing based on?

Answer 20

Antigens and antibodies