Rule Out Diagnosis
Rule out means to eliminate as a possibility. For
example, a doctor may have a patient's blood pressure
tested to rule out high blood pressure. That is, the
doctor wants to know if the results from the test will
eliminate the possibility that the patient has high blood
pressure. Rule out is commonly abbreviated as R/O in
medical charts. In the example above, the doctor's note
to the health care worker that performs the test may
say: R/O high blood pressure. It is important to note
that this does not mean that the patient has been
diagnosed with high blood pressure. In doctor notes,
rule outs are typically listed underneath a diagnoses
that have already been established.
FEATURED BOOK: Differential Diagnosis of Common Complaints

For example, under the diagnosis section in the note it may say: 1.) Migraine headaches,
2) High cholesterol, 3) R/O multiple sclerosis.

In the above example, the doctor is saying that it is already known that the patient has
migraine headaches and high cholesterol but that it is unknown if the patient has multiple
sclerosis. Multiple sclerosis is a condition in which people develop multiple areas of
abnormal patches (also known as plaques or sclerosis) in the brain and/or spinal cord
(depending on the stage of the illness). To investigate this rule out further, the doctor will
order various studies such as those that provide pictures of the brain.

"Where Medical Information is Easy to Understand"™