Sensitivity
Say it: sen-sih-TIV-ih-tee
Sensitivity is the proportion of people who truly have a condition whom a diagnostic or screening test correctly identifies as positive.
Also: true positive rate
Definition
What is sensitivity?
In medicine and epidemiology, sensitivity describes how well a test detects a condition in people who really have it. It is calculated by dividing the number of true positives (affected people who test positive) by everyone who actually has the condition, that is, the true positives plus the false negatives. A test with 90 percent sensitivity picks up 90 of every 100 affected people and misses 10, who receive a false-negative result.
Sensitivity is judged against a reference standard, the best available way of confirming who has the disease. It often trades off against specificity: lowering the cutoff for calling a result positive catches more true cases but also flags more healthy people. A highly sensitive test is valuable for screening and for ruling a disease out, summed up in the mnemonic SnNout: when sensitivity is high, a negative result helps rule the condition out. Sensitivity does not tell a patient how likely a positive result is to be correct; that is the positive predictive value, which depends strongly on how common the condition is.
Outside test evaluation, the word is used more loosely for how strongly a person reacts to a drug, chemical or sunlight.
Word parts
Where does the word “sensitivity” come from?
- sens-
- sense, feelingLatin sensus
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Related
Terms that go with it
- SpecificitySpecificity is the proportion of people who do not have a condition whom a diagnostic or screening test correctly identifies as negative.
- PrevalencePrevalence is the share of a population living with a particular disease or condition, either at one point in time or across a set period.
- ELISAELISA is a lab test that uses enzyme-linked antibodies to detect and measure a specific antigen or antibody in a sample through a color change.
- EpidemiologyEpidemiology is the study of how often diseases and other health events occur in populations, what causes them and how they can be controlled.
- Polymerase chain reactionThe polymerase chain reaction (PCR) is a lab technique that copies one chosen stretch of DNA over and over until there are billions of copies.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- NCI Dictionary of Cancer Terms: sensitivity
- Trevethan (2017), Sensitivity, Specificity, and Predictive Values: Foundations, Pliabilities, and Pitfalls
- American Heritage Dictionary: sensitive
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