Test or procedure result indicating a normal or negative result when, in fact, an abnormal condition is actually present. A test is said to be sensitive when it has a low false-negative rate. An insensitive test has a high false-negative rate and should not be relied upon to exclude abnormality or disease.
For example, an electrocardiogram for heart disease is relatively insensitive - many patients with coronary artery disease, including acute heart attacks, have a negative result. Other tests, such as nuclear medicine treadmill scans, are far more sensitive because they have a much lower percentage of false-negative results.