Equation Review

Question 1

Sensitivity

Answer 1

Sensitivity = TP / (TP + FN)

Question 2

Specificity

Answer 2

Specificity = TN / (TN + FP)

Question 3

Positive predictive value

Answer 3

PPV = TP / (TP+ FP)

Question 4

Negative predictive value

Answer 4

NPV = TN/ (FN + TN)

Question 5

Odds ratio (for case-control studies)

Answer 5

OR = (a/c) / (b/d) = ad / bc

Question 6

Relative risk

Answer 6

RR = [a / (a+b)] / [c / (c+d)]

Question 7

Attributable risk

Answer 7

AR = [a / (a+b)] - [c / (c+d)]

Question 8

Relative risk reduction

Answer 8

RRR = 1 - RR

Question 9

Absolute risk reduction

Answer 9

ARR = [c / (c+d)] - [a / (a+b)]

Question 10

Number needed to treat

Answer 10

NNT = 1/absolute risk reduction

Question 11

Number needed to harm

Answer 11

NNH = 1/attributable risk

Question 12

Hardy-Weinberg equilibrium

Answer 12

p^2 + 2pq + q^2 = 1

p + q = 1

Question 13

Volume of distribution

Answer 13

Vd = (amount of drug in the body) / (plasma drug concentration)

Question 14

Half-life

Answer 14

t sub (1/2) → t(1/2) = (0.693 X Vd) / CL

Question 15

Drug clearance

Answer 15

CL = (rate of elmination of drug) / (plasma drug concentration) = Vd x Ke (elimination constant)

Question 16

Loading dose

Answer 16

LD = (Cp X Vd) / F

Question 17

Maintenance dose

Answer 17

D = (Cp X CL X τ ) / F

Question 18

Cardiac output

Answer 18

CO = (rate of O2 consumption) / (arterial O2 content - venous O2 content)

CO = stroke volume x heart rate

Question 19

Mean arterial pressure

Answer 19

MAP = cardiac output X total peripheral resistance

MAP= (2/3) diastolic + (1/3) systolic

Question 20

Stroke volume

Answer 20

SV = EDV - ESV

Question 21

Ejection fraction

Answer 21

EF =