Screening testing in health care: Getting it right.
The Journal of the American Dental Association, Volume 153, Issue 4, April 2022, Pages 365-370.
Glick M, Carrasco-Labra, A.
Oral health care professionals often wish to screen individuals for contagious diseases and other medical conditions to identify systemic conditions that may impact their oral care. Whether screening for COVID-19, HPV, high blood pressure or a host of other medical conditions, it is important to not only choose an appropriate test, but also be able to effectively interpret results.
To assist oral health care professionals in interpreting test results, Penn Dental Medicine has created this electronic web-based tool – the Disease Screening Interpretation Calculator (DSIC) – that provides information to assist a clinician in making appropriate clinical decisions that are based on the outcome of a screening test.
A screening test for a medical condition can usually not provide a 100% certainty of a patient’s medical status – there will always be a certain percentage of false negative (FN) and false positive (FP) results. However, the DSIC will provide the probability of a positive test result being a true positive (TP). This probability is called the positive predictive value (PPV). The DSIC will also provide the probability of a negative test result being a true negative (TN). This probability is called the negative predictive value (NPV).
There are three different variables that will determine a PPV and NPV – the prevalence of the condition (i.e. for COVID-19, the transmission level in the patient’s community or for other medical conditions, the prevalence in a patient population), the sensitivity, and the specificity of the test being used. A test’s sensitivity is the test’s ability to detect TP cases among all the cases with the condition, while the specificity is a test’s ability to detect TN cases among all the cases without the condition. A test’s sensitivity and specificity values are acquired from the test/device manufacturer.
Once care providers know the PPV and the NPV of a test result and how to communicate positive and negative test results with patients, oral health care professionals will be able to better decide on how to treat a patient with a certain test result, generate appropriate medical referrals, determine the need for further testing, as well as provide a public service.
Follow the instructions below to use the calculator.