Philosophical Heritage
"When you have eliminated the impossible, whatever remains, however improbable, must be the truth. "

- Sherlock Holmes, The Sign of Four, 1890

Accuracy of Tests
Diagnostic tests must be correlated with the clinical situation. No test is perfect. A falsely positive tests occurs when the test represents that a condition exists in a patient but the findings of the test do not represent what is wrong with the patient. A falsely negative test occurs when the test represents a condition does not exist in a patient but the condition does exist in the patient.

Sensitivity and Specificity of Tests
A test is sensitive if it can detect a problem. A test is specific if it can detect the problem. As human beings mature, they collect changes in the spine which may exist without causing symptoms. However, those very same changes may produce symptoms in a particular individual. Testing must identify these two groups.

Correlation
The tests must correlate with the patient's clinical symptoms and clinical condition. The Clinician understands that is his/her role in diagnosis. Understanding the relative value of the tests in relationship to the patient's clinical condition is the key strategy.