Diagnosis of Lupus
23. Is there a test for systemic lupus?
There is not a single diagnostic test for systemic lupus.
See: Laboratory Tests Used in the Diagnosis of Lupus
24. Why is systemic lupus so difficult to diagnose?
It is difficult for a number of reasons:
- Systemic lupus is a multi-system disease, and before a multi-system disease can be diagnosed, there have to be symptoms in many parts of the body and lab work that supports the presence of a multi-system disease.
- Systemic lupus is also difficult to diagnose because it is a disease that does not typically develop rapidly, but rather develops slowly and evolves over time. Symptoms come and go and it generally takes time to gradually accumulate enough symptoms to indicate that a multi-system disease is present. The
- Systemic lupus is known as a Great Imitator because it mimics so many other diseases and conditions.
- Systemic lupus is difficult to diagnose because there is no single diagnostic test for lupus. In fact, many people may have positive lupus tests-particularly the anti-nuclear antibody test-and yet NOT have the disease.
How is systemic lupus diagnosed?
Physicians have to gather information from a variety of sources: past medical history, lab tests and current symptoms. They use a list of 11 criteria to help diagnose SLE. A person needs to satisfy at least 4 out of the 11 criteria before the diagnosis can be pinpointed. Some criteria, such as a biopsy diagnosis of kidney lupus, can carry more weight.
Of the 11 criteria, 7 relate to symptoms, and 4 have to do with lab tests. The ANA test is used as a screening test for systemic lupus. We know that 95 % of people with SLE have a positive ANA. Therefore, if a person has many symptoms of systemic lupus and their ANA test is negative, that's generally regarded as pretty good evidence against lupus being the explanation for the symptoms they are having.
If on the other hand, the ANA comes back positive, that IS NOT proof of lupus. The positive ANA is only an indicator; it is not diagnostic. A positive ANA can be found in a number of illnesses and conditions including:
- Rheumatoid arthritis
Sjogren's (show-grens) syndrome
Infectious diseases such as:
Subacute bacterial endocarditis (SBE)
Autoimmune diseases including:
Autoimmune thyroid disease
Autoimmune liver disease
Certain medications can also cause a positive ANA. About 20% of the general population when tested will have a positive ANA and not have any of the above mentioned illnesses. The ANA is only a test and like a high cholesterol value, a positive ANA doesn't necessarily equate having a disease.
So, a positive ANA, by itself, is not diagnostic of any one particular disease and may be present in people who have no illness. Although it is often referred to as "a lupus test," it is not like a pregnancy test where a positive result can mean only one thing. The ANA is only an indicator, which points in several possible directions. A positive ANA satisfies only one criterion. A person would need to satisfy at least 3 additional criteria.
See: Laboratory Tests Used in the Diagnosis of Lupus
25. Confusion About Diagnosis - I've seen a list of symptoms of lupus and I have just about every one. The doctor I went to doesn't think I have lupus, but he doesn't seem to know too much about it. How can I be sure I do or do not have lupus?
Lupus is a very difficult disease to diagnose. Physicians use a list of 11 criteria to assist in the diagnosis. The criteria consist of symptoms and lab tests, which tend to be specific to SLE. The list of 11 criteria is not to be confused with lists of common symptoms of systemic lupus, such as: fatigue, fever, weight loss, hair loss, nausea, Raynaud's phenomenon. These symptoms, could be due to numerous illnesses or conditions, and, therefore, are too vague to be included as diagnostic criteria.
If a person has many of the symptoms of systemic lupus, the physician may suspect lupus is developing, and evaluate the patient to see if any criteria are met. If fewer than 4 criteria are satisfied, there is insufficient evidence to diagnose systemic lupus. A rheumatologist or a clinical immunologist may be consulted if you are looking for a specialist who has the expertise to diagnose and treat lupus.
I am afraid I might have lupus and my doctor is going to miss something and end up diagnosing me with lupus too late. If I have it, I want to be diagnosed as early as possible. How can I make sure I am diagnosed earlier rather than later?
Because lupus tends to develop slowly and evolve gradually over time, awaiting a diagnosis can be like waiting for a Polaroid picture to develop. If you are seen by a doctor at a point in time when only one or two criteria are satisfied, it is like looking at a picture that is only one-quarter or half-way developed. No one looking at that picture can accurately identify what it is. Nor can they predict if it will develop at all or what it will develop into, or how long it will be before it is developed to the point where it's identifiable. Just as there is no good way to speed-up the development of a Polaroid, there is no way to hurry-up the diagnosis of lupus.
The length of time it takes before lupus can be diagnosed is highly variable; it may take weeks, months or years; three years is not an uncommon length of time for many people to have symptoms before being diagnosed. In some cases, it can take as long as 10 years before enough evidence has accumulated to indicate that it is lupus. However, generally a doctor has a pretty good idea, though s/he may not be certain, that a person does or does not have SLE. The important thing is to learn the signs and symptoms of lupus and if you develop something new, let your doctor know so s/he can determine if you have yet satisfied enough criteria to be diagnosed.
My doctor suspects I have lupus, but hasn't diagnosed me with it yet. I have a lot of joint pain in my hands and knees. Can anything be prescribed to give me some relief, or do I have to wait until I have a definite diagnosis before they can treat me?
Sometimes, a trial of lupus medications is helpful, so discuss this with your doctor.
My Doctor said my lupus test came back "borderline positive." What does this mean?
The screening test for lupus is called the ANA (antinuclear antibody). All lab tests have normal values. If a test result comes back and the value is at the upper limit of normal, this is often referred to as being on the border or borderline. These results are often very difficult to interpret; and the assessment of its importance is dependent on meeting other criterion. It is likely that a borderline positive ANA assumes more importance if other criteria are also present.
I was told my ANA was positive, but I don't have lupus. My Doctor thinks I have a connective tissue disease. What does this mean?
Connective tissue includes joints, tendons, cartilage, collagen, muscles and skin. There are a number of connective tissue diseases; rheumatoid arthritis, scleroderma, Sjogren's syndrome, Raynaud's phenomenon, vasculitis, polymyositis and dermatomyositis. It is not uncommon for a person to have symptoms that indicate a connective tissue disease, but not enough symptoms to clearly specify a particular disease.
See: Lupus in Overlap with other Connective Tissue Diseases, Lupus: Basics for Better Living, "My ANA is Positive...What Does That Mean?"
I was told my ANA was negative, and I don't have lupus. Is it possible to have lupus with a negative ANA?
Approximately 95% of people with systemic lupus have a positive ANA. Only a small percentage have a negative ANA, and many of those have other antibodies detected in their blood (antiphospholipid antibodies, anti-Ro, anti-SSA). Sometimes the ANA will convert from positive to negative following administration of steroids, cytotoxic medications or uremia (kidney failure).
What kind of Doctor can diagnose systemic lupus?
If multiple criteria are present simultaneously, the diagnosis may be made by any physician (Family Practitioner, Internist, Pediatrician). If however, as is often the case, symptoms develop gradually over time, the diagnosis may not be as obvious and consultation with a rheumatologist may be needed.
My doctor suspects that I may be developing lupus, but I don't satisfy enough criteria to be diagnosed. Is there anything I can do to slow its development or prevent it from occurring?
If you are indeed developing lupus, there is no known way of arresting it. You can, however, be an active participant in your well being by:
- learning as much as you can about lupus so if you develop further symptoms, you will recognize them and notify your doctor,
- eating a well balanced diet,
- managing stress more effectively, and
- following your doctor's advice.
I was told my ANA was positive and I have a lot of pain, but my doctor thinks I have fibromyalgia and not lupus. What does this mean?
Patients with positive ANA's and muscle and joint pain do not necessarily have lupus. Fibromyalgia, which is also common in women, sometimes explains the widespread pain.
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The National Library of Medicine's MEDLINE Plus: Health Information-Fibromyalgia