Lupus - And you wonder why they call it the allusive disease..

January 1, 2003

So .. you have had your blood drawn and the results for your ANA come back

positive.

So .. do you have lupus .. or not?

Diagnosing lupus is a complex process. It's not as simple as diagnosing

a broken bone, strep throat, or pregnancy. In these conditions there are

simple tests which, if positive, point to a single diagnosis. There is

no single diagnostic test for lupus.

There is a screening test called the ANA (anti-nuclear antibody) test

which is often checked when a doctor suspects lupus. If the ANA test comes

back negative it is considered a normal result, and it is very good evidence

against lupus as an explanation for the symptoms.

If the ANA test result comes back above the normal range the test is

said to be positive. A positive ANA test by itself is not proof of lupus,

but then again, having a negative result does not necessarily mean you

don't have lupus.

(Confused yet?)

What does a positive ANA mean? Unlike a pregnancy test, which if positive

generally means only one thing, a positive ANA can mean many things.

There are many illnesses and conditions associated with a positive ANA,

including:

rheumatoid arthritis

Sjogren's syndrome

scleroderma

lupus

mononucleosis

syphilis

subacute bacterial endocarditis

autoimmune thyroid and liver disease.

Certain medications can cause a positive ANA, and many healthy people

with no associated illness or condition have a positive ANA. In fact, about

5% of the general population will have a positive ANA yet fewer than 1

in 1,000 have lupus. Thus, at least 95% of the people who have a positive

ANA do not have lupus!

A positive ANA test can sometimes run in families, even if family members

have no evidence of lupus. The ANA is only a test and, like a high cholesterol

value, a positive ANA doesn't necessarily equate having a disease. A positive

ANA is only an indicator which points in several possible directions, and

indicates that further investigation and analysis may be needed.

Recommended Posts