NR 511 Differential Diagnosis and Primary Care – Midterm Review Exam Questions and Answers – Comprehensive Study and Exam Preparation Material

NR 511 DIFFERENTIAL DIAGNOSIS AND PRIMARY CARE




NR 511 DIFFERENTIAL DIAGNOSIS AND PRIMARY CARE- MID TERM
REVIEW EXAM QUESTIONS AND ANSWERS GRADED A+




1. what is the sensitivity of the Prostate Specific Antigen (PSA) for
detecting prostate cancer? # men with prostate cancer
# men with positive
PSA 160

# men with negative
PSA 40

total
200

The correct answer is 160/200. Sensitivity is the proportion of patients with the disease that
have a positive result; it is the number of true positives divided by the total number of
patients who have the disease.
2. A diagnostic test is used in a sample of 1000 patients. 500 of these
patients have the disease, while 500 do not. Of those 500 patients
without the disease, 30 test positive, and 470 test negatives. What is
the specificity of the test? The correct answer is 470/500.



,NR 511 DIFFERENTIAL DIAGNOSIS AND PRIMARY CARE




Specificity is the proportion of patients who test negative out of the total number of
patients who do not have the disease; it is the number of true negatives overall negatives. In
this example, 500/1000 patients have the disease. Of those 500 patients without the disease,
30 test positive, and 470 test negatives.
3. The Positive Predictive Value (PPV) of a test refers to which of the
following? -
: the proportion of patients with a positive test who have the disease.
4. Which of the following depends on the prevalence of the disease?
positive predictive value.

Predictive values depend on the prevalence of disease in the population whereas sensitivity and
specificity are intrinsic properties of the test. Reliability refers to the consistency or stability
of a measure.
5. A low pretest probability of disease may lead to which of the
following? low positive predictive value and more false-positive results.

Positive predictive value increases with prevalence; therefore, a low prevalence value yields a low
positive predictive






,NR 511 DIFFERENTIAL DIAGNOSIS AND PRIMARY CARE




value and implies a high false-positive rate. Negative predictive value decreases with
prevalence, and sensitivity and specificity do not vary with prevalence.
6. If you strongly suspect that a patient is positive for a specific
condition but tests negative, the negative result may be: false-negative test
results due to a low negative predictive value.

At the individual level, your clinical suspicion is equivalent to pre-test probability and high
prevalence at the population level. Negative predictive value is inversely correlated with
prevalence; therefore, your clinical suspicion translates to a low negative predictive value,
suggesting a false-negative test result.
7. Which test(s) provide data relevant to the chief complaint: Fever: CBC


Check CBC with deterrently for neutrophil shift in suspected infection
8. Which test(s) provide data relevant to the chief complaint:
Unexplained bruising: CBC

Check platelet count
9. Which test(s) provide data relevant to the chief complaint: Fatigue:
Both CBC and CMP

Check RBC, Hgb and Hct for anemia, CMP for potential liver or kidney abnormalities
10. Which test(s) provide data relevant to the chief complaint: Cardiac
dysrhythmias: CMP

Monitor electrolytes for abnormalities
11. Which test(s) provide data relevant to the chief complaint:
Unexplained weight loss: Both CBC and CMP



,NR 511 DIFFERENTIAL DIAGNOSIS AND PRIMARY CARE




Check WBC for inflammation or possible cancer, CMP for glucose, liver or kidney abnormalities
12. Which test(s) provide data relevant to the chief complaint: Edema:
CMP

Check for kidney function
13. What is SNAPPS? Summarize the history and
findings Narrow the deterrently diagnosis to two
or three possibilities