Why does lupus tests sometimes come back negative?

There is no such thing as a lupus test per se. Certain test results will help confirm or rule out a lupus diagnosis, but none of them are totally specific or definitive. In other words, not *everyone* with lupus will have a certain result; and a few people who don't have lupus, will have the result.

The most common screening tests for lupus are for erythrocyte sedimentation rate (also known as SED rate or ESR), and antinuclear antibodes (ANA).

About 95% of people with lupus test positive for antinuclear antibodies-- certain parts of the blood that are programmed to attack parts of your own body. On the other hand, ANA also tends to be positive in many other autoimmune conditions; 5 to 10% of people without any autoimmune condition will have positive ANA.

When performing this test, the lab will also check the "titre", that is, the concentration of these antibodies. Generally, patients with lupus have a high titre such as 1:800 (meaning that if the blood is watered down to one part in eight hundred, the antibodies are still found), though this is not always the case and many people with lower titres can be diagnosed. They will also list the pattern in which the ANA occurs-- "speckled" is the most typical for lupus patients.

Most lupus patients will also have an elevated ESR, which basically indicates that your body is currently reacting to an inflammatory condition. Again, though, elevated ESR can occur with many other conditions such as arthritis or inflammatory bowel disease; and it is possible to diagnose lupus without elevated ESR in the presence of classical symptom presentation.

Hi, agree with Colt & Tegan, there are no Lupus tests - though there are tests that can determine the likelyhood of lupus. If you or someone you know has it, you must be frustrated to be asking this question...I'm sorry.

It takes on average, 4 to 7 years to diagnose lupus because of the diversity of the symptoms, the tests that need to be run, the results may vary also due to the patient "FLARES", etc.

Put simply, tests can come back negative if you are not in a FLARE, if certain tests are not administereed at a certain time, hormones play a part in everything, there are a lot of factors. There are also complement tests that are considered. (C2, C3, C4, it goes on.... )

Also remember that your blood tests are only one component of a lupus diagnosis. There are more aspects to an official diagnosis.

Always check with a good Rheumatologist. Ask around for referrals.

If you are interested, here are some basic lupus facts:

Basic Lupus Facts

"Typical" clinical features include:

- Fever, fatigue, and weight loss
- Arthritis involving multiple joints for several weeks
- Butterfly-shaped rash over the cheeks or other rashes
- Skin rash appearing in areas exposed to the sun
- Sores in the mouth or nose for more than a month
- Loss of hair, sometimes in spots or around the hairline
- Seizures, strokes and mental disorders
- Blood clots in different locations
- Miscarriages in some patients
- Blood or protein in the urine or tests that suggest poor kidney
function
- Low blood counts (anemia, low white blood cells or low platelets)

- Other symptoms include chest pain when the patient breathes deeply,
heartburn, abdominal pain and poor circulation to the fingers and
toes.

- All of these symptoms can develop gradually, making lupus hard to
diagnose.
漏 2008 American College of Rheumatology

Lupus affects Asians, Native Hawaiians, Pacific Islanders, African
Americans, Hispanics, Latinos, and Native Americans
disproportionately.

Although it affects women nine times more than men in their child
bearing years, men are affected. Children are affected.

Good luck.