How Are Pathology Tests Interpreted

Question 1

ROC curve

Answer 1

Receiver Operator Characteristics

Question 2

Is it more important to prioritise specificity or sensitivity in a diagnostic test?

Answer 2

Specificity, provided the prevalence of disease is low; this gives a good PPV and a fair NPV (cf prioritising sensitivity which would result in a good NPV and a poor PPV)
If want to rule out disease however, prioritise sensitivity (high NPV)
To rule in prioritise specificity (high PPV)

Question 3

How are reference intervals determined, in order from poorest to best evidence?

Answer 3

Kit insert
Lab survey
Lab experts
Clinical experts or population surveys
Clinical outcomes studies

Question 4

How is uncertainty of tests measured?

Answer 4

SD

Question 5

What 2 factors can introduce uncertainty into the interpretation of a test?

Answer 5

Analytical variability

Biological variability

Question 6

What carries a higher risk of mortality: hypo- or hyper-kalaemia?

Answer 6

Hypokalaemia (hyperkalaemia can be tolerated if accumulates slowly as in CKD)