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A physical therapist utilizes the McMurray test to confirm a suspected medial meniscus tear. Which of the following measures of validity would be the MOST useful for ruling in the diagnosis?

1. Sensitivity of 80%
2. Sensitivity of 20%
3. Specificity of 80%
4.  Specificity of 20%

Transcript

Welcome back to the Scorebuilders’ Question and Answer Podcast! This podcast provides members of the Scorebuilders’ team with the opportunity to explore challenging multiple-choice examination questions with students actively preparing for the licensing examination. My name is Scott Giles and I will be your host for today’s journey.

Ready? Let’s go!

A physical therapist utilizes the McMurray test to confirm a suspected medial meniscus tear. Which of the following measures of validity would be the MOST useful for ruling in the diagnosis?

1. Sensitivity of 80%
2. Sensitivity of 20%
3. Specificity of 80%
4.  Specificity of 20%

Understanding Sensitivity and Specificity
Sensitivity and specificity are measures of validity that help clinicians to determine the accuracy of a medical test.

Sensitivity
Sensitivity refers to the percentage of people who test positive for a specific disease among a group of people who have the disease. 

Specificity
Specificity refers to the percentage of people who test negative for a specific disease among a group of people who do not have the disease.

Interpretation of Sensitivity and Specificity

• High sensitivity and specificity are desirable for diagnostic tests.
• A high sensitivity is important for detecting rare or serious diseases where missing cases can have significant consequences.
• A high specificity is important for avoiding unnecessary interventions or treatments based on false positive results. 

This specific question is asking - Which of the following measures of validity related to the McMurray test would be the MOST useful for ruling in a suspected meniscal tear?

Armed with this information. let’s explore each of the options:
Option 1 - Sensitivity of 80%
Sensitivity describes the accuracy of a test for patients who have the disease. Clinically, tests with high sensitivity can be used to help rule out a condition. If a test has a high sensitivity (e.g., 80%), then it can be used to rule out the condition if the test result is negative. 

The mnemonic SnNOut (Sensitive, Negative, Out) can be used to help clinicians remember how to interpret the test results for a highly sensitive test. Remember, this particular question is attempting to “rule in” not “rule out” the suspected meniscal tear.

Option 2 - Sensitivity of 20%
Sensitivity describes the accuracy of a test for patients who have the disease. A sensitivity value of 20% is very low, which means that the test would not be accurate and therefore not clinically useful.

Option 3 - Specificity of 80%
Specificity describes the accuracy of a test for patients who do not have the disease. Clinically, tests with high specificity can be used to help rule in a condition. If a test has a high specificity (e.g., 80%), then it can be used to rule in the condition if the test result is positive.

The mnemonic SpPIn (Specific, Positive, In) can be used to help clinicians remember how to interpret the test results for a highly specific test.

This is a great answer to the question since the intent was to “rule in” the suspected meniscal tear.

Option 4 - Specificity of 20%
Specificity describes the accuracy of a test for patients who do not have the disease. A specificity value of 20% is very low, which means that the test would not be accurate and therefore is not clinically useful.

The correct answer is Option 3

Let’s explore the all student data:
25% of students selected Option 1, Sensitivity of 80%
5% of students selected Option 2, Sensitivity of 20%
65% of students selected Option 3, Specificity of 80%, the correct response
5% of students selected Option 4, Specificity of 20%

System Classification
This question is a Non-Systems question which represents approximately 14% of all exam items.

Content Outline Classification
This question is a Safety and Protection; Professional Responsibilities; and Research question which represents approximately 8% of all exam items.

Level Classification
This question is a Level 2 question since the question requires students to integrate numerous pieces of information or to apply knowledge in a given clinical scenario. Remediation of Level 2 questions occurs by increasing flexibility with academic content and by carefully analyzing decision making processes when answering applied examination questions.

Academic Focus Area
Looking to review related academic content? Check out page 842 in PTEXAM: The Complete Study Guide.

Thanks for joining us on the Scorebuilders Q and A podcast! See you next week!