MSK2 LR- LR+ Sn Sp

Question 1

Sensitivity

Answer 1

SnOut = ability to detect a TRUE positive from a false positive. So if high sensitivity and test negative, then rules out a condition

Question 2

Specificity

Answer 2

SpIn = ability to detect a TRUE negative from a false negative. So if high specificity and test positive, then this rules in a condition

Question 3

Likelihood ratio

Answer 3

how much more likely a person is to have the condition of interest after a test is performed. Incorporates both SnOut and Sp1n

Question 4

+ LR 1 to 2

Answer 4

interpretation: alters post test probability minimally

Question 5

+ LR 2 to 5

Answer 5

interpretation: alters post-test probability to a small degree

Question 5

+ LR 5 to 10

Answer 5

interpretation: alters post-test probability to a moderate degree

Question 6

+ LR >10

Answer 6

interpretation: significantly alters post-test probability.

Question 7

(-) LR 0.5 to 1

Answer 7

interpretation: alters post-test probability to a small degree

Question 8

(-) LR 0.2 to 0.5

Answer 8

interpretation: alters post-test probability to a moderate degree

Question 9

(-) LR 0.1 to 0.2

Answer 9

interpretation: alters post-test probability to a moderate degree

Question 10

(-) LR Less than 0.1

Answer 10

interpretation: significantly alters post-test probability.

Question 11

Sensitivity function

Answer 11

If the test result is negative, it effectively rules out the disease (high sensitivity means few false negatives).

Question 12

Specificity function

Answer 12

If the test result is positive, it effectively rules in the disease (high specificity means few false positives).

Question 13

alarm system - sensitivity

Answer 13

(rules out pathology) Think of sensitivity as the ability of your security alarm to detect any intruders. A highly sensitive alarm will go off for any small disturbance, even if it’s just a cat or the wind. This means it’s very good at detecting intruders (high sensitivity), but it might also have many false alarms. In medical terms, a test with high sensitivity will catch most people who have the disease (true positives) but might also indicate the disease in healthy people (false positives). If your alarm doesn’t go off (negative result), you can be pretty confident there are no intruders (ruling out pathology).

Question 14

alarm system = specificity

Answer 14

(rules in pathology): Now think of specificity as the ability of your security system to correctly identify real intruders and not be triggered by harmless things. A highly specific alarm will only go off when there is definitely an intruder and not for any other reason. This means it might miss some intruders if they are very sneaky (low sensitivity), but when it does go off, you can be sure there is an intruder (high specificity). In medical terms, a test with high specificity will correctly identify those without the disease (true negatives) and will rarely indicate a disease in healthy people. If your alarm goes off (positive result), you can be confident there is an intruder (ruling in pathology).