How is sensitivity calculated in medical testing?

Sensitivity is a critical measure in medical testing, specifically regarding a test's ability to correctly identify those with the condition being assessed. To calculate sensitivity, one looks at the relationship between true positives and false negatives. Sensitivity is defined as the proportion of actual positives that are correctly identified by the test.

The formula for sensitivity is true positives divided by the sum of true positives and false negatives. This means that you take the number of individuals who tested positive for the condition (true positives) and divide that by the total number of individuals who actually have the condition (which includes both those who tested positive and those who tested negative but actually had the condition, represented by false negatives).

Using this formula allows healthcare professionals to evaluate how well a particular test detects the disease in question, which is essential for making informed decisions regarding diagnosis and treatment options. High sensitivity is particularly valuable in screening tests, where identifying as many true cases as possible is critical.