Specificity is the proportion of people free of disease who have a negative test. Specificity reflects how good the test is at identifying people without the disease. A measure of the diagnostic accuracy in excluding individuals without the condition.

Number of True Negatives divided by (Number of True Negatives + Number of False Positives)

  • True positive: People correctly diagnosed with the condition
  • False positive: Healthy people wrongly diagnosed with the condition
  • True negative: Healthy people correctly identified as healthy
  • False negative: People wrongly identified as healthy