Selecting a Screening/Diagnostic Tool

During Week 2, in the Discussion Board and with the HP2020 Impact Paper, you are asked to select a screening or diagnostic tool to analyze.  You are then required to provide a review of the statistics related to the diagnostic tool, for instance sensitivity, specificity and the predictive value of the screening/diagnostic tool.

What do these terms mean exactly? 

In Chapter three (3) of your textbook Curly & Vitale (2016) discuss the implications of screening and the use of the following values (see the section “Screening”):

FAQ:  What is a…?

1. Screening or diagnostic tool:  Instrument used to detect disease in groups of individuals with the goal of reducing and/or preventing morbidity and mortality.  Examples:  Beck’s Depression Screening Tool, Attention Deficit Screening Tool, Pap smear, mammography, colonoscopy, cologuard or the Mini-Nutritional Assessment screening tool (https://www.ncoa.org/center-for-healthy-aging/resourcehub/community-orgs-and-professionals/professional-resources/malnutrition-screening-tools/).

FAQ:  What is the meaning of…?

• Predictive value of a test:  (PV) is a measure of the probability of a positive test result when the disease is present.

              a. Positive predictive value:  The number of the people who test positive who actually have the disease.

              b. Negative predictive value: The number of the people who test negative who truly do not have the       disease.

• Sensitivity:  measure of a screening test’s ability to accurately identify disease when it is present. The higher the sensitivity of a tool, the fewer the cases that will go undetected and the greater sensitivity of the tool to detect disease.  For example, in-office tests for influenza or for Beta Hemolytic Strep Throat.  They may be specific to influenza BUT are they also sensitive enough to pick up the organism? 

• Specificity:  measure of a screening test’s ability to correctly identify those with the disease and to exclude the persons who do not have the disease.  The higher the specificity of the screening tool the fewer persons will be incorrectly identified at-risk.  So, this means the test is specific to the organism for instance, to influenza, and that it will be up influenza and not mononucleosis for example, of Beta Hemolytic Strep throat. 

• Validity:  ability of the tool to actually measure what it says it measures.

Curley, A.L. & Vitale, P.A. (2016). Population-Based Nursing: Concepts and Competencies for Advanced Practice (2nd ed.). New York, NY: Springer Publishing.