Name:
PGY:
Med or Med/Peds (circle)
EBM - Diagnosis
Pretest
A star researcher at IU develops a fancy new lab test for diagnosing alcoholic hepatitis. It is a lab test drawn at the time
of presentation to an outpatient clinic. She decides to compare it to liver biopsy, the current gold standard. The
following table shows results of her preliminary study. Based on the 2 x 2 table, please answer the questions regarding
statistical terms.
Alcoholic Hepatitis
Test
Positive
Negative
Present
30
20
Absent
10
40
1. Positive Predictive Value
A. 50%, or 0.50
B. 60%, or 0.60
C. 67%, or 0.67
D. 75%, or 0.75
E. 80%, or 0.80
2. Negative Predictive Value
F. 50%, or 0.50
G. 60%, or 0.60
H. 67%, or 0.67
I. 75%, or 0.75
J. 80%, or 0.80
3. Specificity
K. 50%, or 0.50
L. 60%, or 0.60
M. 67%, or 0.67
N. 75%, or 0.75
O. 80%, or 0.80
4. Sensitivity
P. 50%, or 0.50
Q. 60%, or 0.60
R. 67%, or 0.67
S. 75%, or 0.75
T. 80%, or 0.80
5. Positive Likelihood Ratio
a. 0.5
b. 0.67
c. 0.75
d. 1.125
e. 1.33
f. 2
g. 3
h. c’mon Dr. Djuricich, I have no clue
6. Negative Likelihood Ratio
i. 0.5
j. 0.67
k. 0.75
l. 1.125
m. 1.33
n. 2
o. 3
p. c’mon Dr. Djuricich, I have no clue
TURN THE PAGE OVER; THERE ARE MORE QUESTIONS ON THE BACK
Name:
PGY:
Med or Med/Peds (circle)
7. You are seeing a patient in clinic that you are concerned has cancer, based on a constellation of signs and
symptoms. You determine that your pretest probability for this patient having cancer is 50%. Given a test with
a positive likelihood ratio of 5 and a negative likelihood ratio of 0.2, what is the post-test probability for this
patient for a negative test?
A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
K.
L.
2.5%
10%
15%
25%
40%
50%
75%
80%
83%
90%
100%
Cannot calculate; need more information
8. For the same patient, what is the post-test
probability for a positive test?
M. 2.5%
N. 10%
O. 15%
P. 25%
Q. 40%
R. 50%
S. 75%
T. 80%
U. 83%
V. 90%
W. 100%
X. Cannot calculate; need more information
True or False
9. In a highly sensitive test, a positive test result rules in the disease.
10. In a highly specific test, a positive test result rules out the disease.
Name:
PGY:
Med or Med/Peds (circle)
EBM - Diagnosis
Posttest
You are doing research in Derm, and you discover a fancy new lab test, MOLE-1, which can be used to diagnose
melanoma without doing a biopsy. It is drawn at the time of presentation to the Dermatologist’s office. You decide to
compare it to biopsy, the current gold standard. The following table displays results of the preliminary study. Based
on the 2 x 2 table, please answer the questions regarding statistical terms.
Melanoma
MOLE-1
Positive
Negative
Present
150
50
Absent
100
200
1. Negative Predictive Value
J. 50%, or 0.50
K. 60%, or 0.60
L. 67%, or 0.67
M. 75%, or 0.75
N. 80%, or 0.80
2. Specificity
O. 50%, or 0.50
P. 60%, or 0.60
Q. 67%, or 0.67
R. 75%, or 0.75
S. 80%, or 0.80
3. Positive Predictive Value
N. 50%, or 0.50
O. 60%, or 0.60
P. 67%, or 0.67
Q. 75%, or 0.75
R. 80%, or 0.80
4. Sensitivity
P. 50%, or 0.50
Q. 60%, or 0.60
R. 67%, or 0.67
S. 75%, or 0.75
T. 80%, or 0.80
5. Negative Likelihood Ratio
a. 0.25
b. 0.375
c. 0.44
d. 0.889
e. 1.125
f. 2.25
g. 2.67
h. c’mon Dr. Djuricich, I still have no clue
6. Positive Likelihood Ratio
h. 0.25
i. 0.375
j. 0.44
k. 0.889
l. 1.125
m. 2.25
n. 2.67
o. c’mon Dr. Djuricich, I still have no clue
TURN THE PAGE OVER; THERE ARE MORE QUESTIONS ON THE BACK
Name:
PGY:
Med or Med/Peds (circle)
7. You are seeing a patient in clinic that you are concerned that may have DVT, based on a constellation of signs
and symptoms. You determine that your pre-test probability for this patient having a DVT is 40%. Given a test
with a positive likelihood ratio of 2 and a negative likelihood ratio of 0.01, what is the post-test probability for a
positive test?
A.
B.
C.
D.
E.
F.
G.
H.
I.
0.4%
4%
8%
20%
25%
40%
60%
80%
Cannot calculate; not enough information
8. For the same patient, what is the post-test
probability for a negative test?
A.
B.
C.
D.
E.
F.
G.
H.
I.
0.4%
4%
8%
20%
25%
40%
60%
80%
Cannot calculate; not enough information
True or False
9. In a highly specific test, a positive test result rules in the disease.
10. In a highly sensitive test, a negative test result rules in the disease.
Name:
PGY:
Med or Med/Peds (circle)
EBM - Diagnosis
Posttest Final
You are doing research in Pulmonary, and you discover a new test, Pleuride, which can be used to diagnose pleural TB
without doing a biopsy. It is drawn at the time of presentation to the Pulmonologist’s office. You decide to compare it
to biopsy, the current gold standard. The following table displays results of the preliminary study. Based on the 2 x 2
table, please answer the questions regarding statistical terms.
Pleural TB
Pleuride
Positive
Negative
Present
20
10
Absent
5
15
1. Specificity
S. 50%, or 0.50
T. 60%, or 0.60
U. 67%, or 0.67
V. 75%, or 0.75
W. 80%, or 0.80
2. Sensitivity
S. 50%, or 0.50
T. 60%, or 0.60
U. 67%, or 0.67
V. 75%, or 0.75
W. 80%, or 0.80
3. Positive Predictive Value
A. 50%, or 0.50
B. 60%, or 0.60
C. 67%, or 0.67
D. 75%, or 0.75
E. 80%, or 0.80
4. Negative Predictive Value
P. 50%, or 0.50
Q. 60%, or 0.60
R. 67%, or 0.67
S. 75%, or 0.75
T. 80%, or 0.80
5. Positive Likelihood Ratio
a. 0.25
b. 0.375
c. 0.44
d. 0.889
e. 1.125
f. 2.25
g. 2.67
h. c’mon Dr. Djuricich, I still have no clue
6. Negative Likelihood Ratio
h. 0.25
i. 0.375
j. 0.44
k. 0.889
l. 1.125
m. 2.25
n. 2.67
o. c’mon Dr. Djuricich, I still have no clue
TURN THE PAGE OVER; THERE ARE MORE QUESTIONS ON THE BACK
Name:
PGY:
Med or Med/Peds (circle)
7. You are seeing a patient in clinic that you are concerned may have lupus, based on a constellation of signs
and symptoms. You determine that your pre-test probability for this patient having lupus is 20%. Given a test
with a positive likelihood ratio of 10 and a negative likelihood ratio of 0.5, what is the post-test probability for a
positive test?
J.
K.
L.
M.
N.
O.
P.
Q.
R.
1.5%
4%
8%
20%
40%
50%
75%
85%
Cannot calculate; not enough information
8. For the same patient, what is the post-test
probability for a negative test?
J.
K.
L.
M.
N.
O.
P.
Q.
R.
1.5%
4%
8%
20%
40%
50%
75%
80%
Cannot calculate; not enough information
True or False
9. In a highly sensitive test, a positive test result rules in the disease.
10. In a highly specific test, a negative test result rules in the disease.