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Flashcards in Biochemistry Tests Deck (13):
1

What is Accuracy when it comes to biochemical testing?

how close the result is to the true value

2

What is precision when considering biochemical testing?

How often the same result is found when repeated - not necessarily accurate!

3

When might you get a false positive?

When the normal for that person falls outwith the reference interval for that test

4

Sensitivity is...

the percentage of people with a disease who have a positive result

5

Specificity is...

the percentage of people without a disease that test as having a normal parameter

6

The positive predictive value is...

% of people who have a positive test who have the disease

 

TP/TP+FP

7

The negative predictive value is...

% of people with a negative test that don't have a disease

 

TN/FN+TN

8

Prevalence is...

% of people tested who have the disease

TP + FP/TP+FP+TN+FN

 

measure of how common the disease is in the population of people who have been tested

9

What does prevalence affect?

Positive Predictive Value

 

Negative Predictive Value

10

As prevalence falls...

a. PPV falls

b. NPV falls

 

As prevalence falls, PPV falls and NPV rises

11

What remains the same regardless of prevalence?

sensitivity and specificity

12

When are tests most useful?

When a disease is has more than 50% prevalence

13

Why is troponin useful in diagnosing an MI?

because the heart is the only tissue that produces it