Sensitivity & Specificity Summary with Example
November 27, 2019 
EU MDR
Sensitivity
Sensitivity measures how often a test/device correctly generates a positive result for people who have the condition that’s being tested for (also called positive control). A test/device that’s highly sensitive will flag almost everyone who has the disease and not generate many false-negative results.
Sensitivity is a method to detect how accurately a device or test or drug is performing its role. Take for example a protein which is specifically express in one tissue; An antibody was developed to determine the expression of that protein by using IHC method is called the IVD device in this example; To detect the Sensitivity of that antibody, IHC study should perform on both known positive control, negative control. A Positive control should show positive and negative control should show negative expression by using this antibody.
Intra and inter runs: Intra run is test results of the same lot# of manufactured device/drug/test kit on different days. Intra run explains about the reliability of the product performance. Inter run is the test results of different Lot# (minimum 3 lots) manufactured on different dates on different samples. Inter run explains the reproducibility of products performance.
Summary to detect Sensitivity for the claimed test/IVD/drug:
- The Literature search for the same or similar kind of device performed in different patients or tissues to find out the device's purpose and exact role
- Literature search to detect cases and controls
- There should be inclusion and exclusion criteria for the literature search
- Also, it is very important that there should be Inter and Intra runs to be run with good results
Specificity
Specificity measures a test’s/device’s ability to correctly generate a negative result for people who don’t have the condition that is being tested for (also called negative control). A high-specificity test will correctly rule out almost everyone who doesn’t have the disease and won’t generate any false-positive results.
Sensitivity and Specificity are the methods to detect how specifically a device or test or drug is performing its role. Specificity is most the important in IVD validation.
Intra and inter runs: Intra run is test results of the same lot# of manufactured device/drug/test kit on different days. Intra run explains about the reliability of the product performance. Inter run is the test results of different Lot# (minimum 3 lots) manufactured on different dates on di erent samples. Inter run explains the reproducibility of product performance.
Summary to detect Specificity for claimed test/IVD/drug:
- Specificity can be detected by the same method/procedure followed in sensitivity
- Literature search for same or similar kind of device performed in different patients or tissues to find out the device purpose and exact role
- Literature search to detect case and controls
- There should be inclusion and exclusion criteria for literature search
- Also it is very important that there should be Inter and Intra runs to be run with good results