From the Guidelines
Sensitivity is considered high when a diagnostic test correctly identifies 95% or more of individuals with a condition, as seen in the tuberculin skin test (TST) with a sensitivity of 95%–98% 1. This threshold is crucial in diagnosing conditions like tuberculosis, where missing cases can have severe consequences.
- High sensitivity tests are valuable for ruling out conditions, as a negative result provides strong evidence that the condition is absent.
- The trade-off is that highly sensitive tests may produce more false positives, which is why they're often paired with more specific confirmatory tests.
- In the context of anaphylaxis diagnosis, the NIAID anaphylaxis diagnostic criteria have a sensitivity of 95% 1, highlighting the importance of high sensitivity in acute and life-threatening conditions.
- The mathematical calculation for sensitivity is the number of true positives divided by the sum of true positives and false negatives, making it a critical metric in evaluating diagnostic tests.
- A high sensitivity test like the TST is ideal for initial screening, especially in high-risk populations, as it helps identify individuals who require further evaluation or treatment, ultimately improving morbidity, mortality, and quality of life outcomes.
From the Research
Definition of Sensitivity
- Sensitivity denotes the proportion of subjects correctly given a positive assignment out of all subjects who are actually positive for the outcome, indicating how well a test can classify subjects who truly have the outcome of interest 2.
- It is a measure of how well a test can detect true positives.
Considerations for High Sensitivity
- A high sensitivity is usually considered to be above 90% 3.
- However, the definition of high sensitivity can vary depending on the context and the specific test being used.
- In general, a test with high sensitivity is useful for ruling out a disease or condition when the test result is negative.
Relationship with Other Metrics
- Sensitivity is inversely related to specificity, wherein one increases as the other decreases 2.
- Positive and negative predictive values do inherently vary with pre-test probability (e.g., changes in population disease prevalence) 2.
- High sensitivity can be useful in screening contexts, but it is important to consider the predictive values as well 3, 4.
Applications of High Sensitivity Tests
- High sensitivity tests can be used to detect diseases or conditions in their early stages 3.
- They can also be used to monitor the effectiveness of treatments or interventions 5, 6.
- However, high sensitivity tests can also produce false positives, which can lead to unnecessary further testing or treatment 4.