# Sensitivity and specificity

Source: https://onco.cc/terms/sensitivity-specificity/  
OnCo record `sensitivity-specificity` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Sensitivity is the share of people with the disease a test catches; specificity is the share of healthy people it correctly clears. No test scores 100% on both, and for screening the trade-off decides how many false alarms you get.

## Summary

Sensitivity (true-positive rate) and specificity (true-negative rate) are properties of the test at a chosen cut-off and are usually estimated against a reference standard such as colonoscopy or biopsy in a study like ECLIPSE or BLUE-C. What a person experiences, the chance that a positive result is real, is the positive predictive value, which depends on how common the disease is: at a 1% cancer prevalence, a test with 99% specificity still generates about as many false positives as true positives. Screening tests trade sensitivity against specificity by moving the cut-off; a multi-cancer blood test set to high specificity (99.5% for Galleri) accepts low sensitivity for early-stage cancer. Sensitivity for precancerous lesions, not cancer, is what distinguishes tests that prevent colorectal cancer from tests that detect it.

## Fields

- Kind: Term
- Last checked: 2026-09-10

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Sensitivity_and_specificity
- Wikipedia: https://en.wikipedia.org/wiki/Sensitivity_and_specificity

## Connected records

- terms: [Overdiagnosis](https://onco.cc/terms/overdiagnosis/), [Positive predictive value (PPV)](https://onco.cc/terms/ppv/), [Screening](https://onco.cc/terms/screening/)
- trials: [BLUE-C](https://onco.cc/trials/blue-c/), [DeeP-C](https://onco.cc/trials/deep-c/), [ECLIPSE (Shield blood test)](https://onco.cc/trials/eclipse-shield/), [INSITE](https://onco.cc/trials/insite/), [PREEMPT CRC](https://onco.cc/trials/preempt-crc/), [PSMA-PreRP](https://onco.cc/trials/psma-prerp/)
- key papers: [Performance of a multi-cancer early detection test in the randomized controlled NHS-Galleri trial](https://onco.cc/key-papers/paper-nhs-galleri-performance-nat-med-2026/)
- drugs: [Afirma Genomic Sequencing Classifier](https://onco.cc/drugs/afirma/), [Cologuard Plus](https://onco.cc/drugs/cologuard-plus/), [SimpleScreen CRC](https://onco.cc/drugs/simplescreen-crc/)
- technologies: [Hand-held and point-of-care ultrasound](https://onco.cc/technologies/hand-held-ultrasound/), [Quantitative imaging biomarkers (RECIST, PERCIST, SUV, ADC)](https://onco.cc/technologies/quantitative-imaging-biomarkers/), [Serum tumour markers: proper use and misuse](https://onco.cc/technologies/serum-tumour-markers/), [Urine tests for bladder cancer (cytology, FISH, RNA and methylation)](https://onco.cc/technologies/urine-bladder-cancer-tests/), [Visual inspection with acetic acid (VIA) for cervical screening](https://onco.cc/technologies/via-cervical-screening/)

---
JSON: https://onco.cc/api/v1/entities/sensitivity-specificity.json