calculations

Question 1

sensitivity =

Answer 1

TP / TP + FN

Question 2

Specificity =

Answer 2

TN / TN + FP

Question 3

PPV =

Answer 3

TP / TP + FP

Question 4

Likelihood ratio of positive test =

Answer 4

Sensitivity / (1-specifity)

Question 5

CV=

Answer 5

SD/mean x 100

Question 6

anion gap =

Answer 6

ANION GAP = Na - Cl - HCO₃

Normal gap = 12 +/- 4

Question 7

osmol gap=

Answer 7

If glucose and BUN is in mg/dl

osmol gap= Osm_measured - (2Na + gluose/18 + BUN/2.8)

OR

If glucose and BUN is in mmol/l aka international units

osmol gap= Osm_measured - (2Na + gluose + BUN)

Normal osmol gap = 10 mOsm/kg

Question 8

NPV =

Answer 8

TN / TN + FN

Question 9

Reticulocyte proliferation Index

RPI =

Answer 9

Retic % X HCT/45 x 1/MI

MI : Maturation Index

RPI > 2 appropriate erythropoietic response

RPI = 2, inappropriate response

Question 10

INR +

Answer 10

INR = (PT_patient / PT_normal) ^ISI

Question 11

MCV =

MCHC =

Answer 11

MCV = Hct % x 10/RBC (millions/uL)

MCHC = (Hgb/Hct) x 100

Question 12

Corrected Count Increment

CCI =

Answer 12

CCI= Observed increment x BSA / # platlets transfused

>7500 is adequate

Question 13

Corrected WBC =

Answer 13

Corrected WBC = Uncorrected x 100/100+NRBCs

Question 14

Blood volume =

Plasma Volume =

Answer 14

Blood volume = Weight (kg) x 70ml/kg

Plasma Volume = (1-Hct) x BV

Question 15

Required Factor 8

How many bags?

Answer 15

= PV (dl) x 1 unit/ dL x % increment

Number of bags of cryo = Required factor 8 units/ 80

There are approximately 80 units of F8 in 1 cryo bag

Question 16

Fractional excretion of sodium

FENa=

Answer 16

FENa= (urine _Na x plama _creatinine) / (urine_creatinine x plasma _Na)

FENa 1% : glomerular disease, hepatorenal

FENa >1 % : ATN, Pre/post renal azotemia

Question 17

GFR =

Creatinine clearancec =

Answer 17

GFR = (140-Age) x Wt (kg) / Cr x 72

Creatinine clearance = GFR or

Volume _urine x Urine _creatinin / plasma _creatinine