True Negative
What is a True Negative outcome?
A true negative (TN) outcome is when an individual is not given any tissue diagnosis of cancer within one year of a negative examination (Funaro et al., 2021).
Example of True Negative from the ACR BI-RADS Atlas:
True Negative: “A woman has a screening examination that is read as negative or benign and no breast cancer is diagnosed within 1 year of the examination. The interpretation is negative, and because no cancer is diagnosed within 1 year, the examination is classified as true-negative (TN)” (Sickles et al., 2013).
What are the two different types of True Negative outcomes in the mammography audit?
Mammologix recognizes two different types of TN outcomes:
- TN1: Asymptomatic patients given an Initial negative assessment and then a negative outcome within 1 year of examination (includes those w/ "No Outcome").
TN2: Asymptomatic mammogram patients given a final negative assessment and then a negative outcome within one year of examination (excludes those w/ "No Outcome")
Why is the time interval for qualifying mammogram outcomes 1 year between the initial assessment and the resulting outcome?
The BI-RADS Atlas states that the reason the time frame for tissue diagnosis after an initial examination is one year is because screening mammograms are recommended to be conducted once a year in the United States (Sickles et al., 2013).
Sources:
Sickles, EA, D'Orsi CJ, Bassett LW, et al. (2013). ACR Bl-RADS Mammography. In: ACR Bl-RADS Atlas, Breast Imaging Reporting and Data System. American College of Radiology. https://www.acr.org/Clinical-Resources/Reporting-and-Data-Systems/Bi-Rads#Mammography
Funaro, K., Ataya, D., & Niell, B. (2021). Understanding the Mammography Audit. Radiologic Clinics of North America, 59(1), 41–55. https://doi.org/10.1016/j.rcl.2020.09.009