New to Lupus? Start Here! Pt.8

Laboratory Tests

Symptoms, Signs and Tests

Because many symptoms of systemic lupus erythematosus (SLE) mimic those of other illnesses, lupus can be a difficult disease to diagnose. Diagnosis is usually made by a careful review of three factors:

• the individual's entire medical history
• an analysis of the results obtained in routine laboratory tests and
• some specialized tests related to immune status.

To make a diagnosis of SLE, an individual must show clinical evidence of a multi-system disease (i.e. has shown abnormalities in several different organ systems). Typical symptoms or signs that might lead to suspicion of SLE are:

Skin: Butterfly rash across the cheeks; ulcers in the mouth; hair loss.
Joints: Pain; redness, swelling.
Kidney: Abnormal urinalysis suggesting kidney disease.
Lining membranes: Pleurisy (inflammation of the lining of the lung); pericarditis (inflammation of the heart lining); and/or peritonitis (inflammation around the abdomen). Taken together, these types of inflammation are known as polyserositis.
Blood: Hemolytic anemia (the red cells are destroyed by autoantibodies); leukopenia (low white blood cell count); thrombocytopenia (low number of platelets).
Lungs: Infiltrates (shadowy areas seen on a chest x-ray) that come and go
Nervous system: Convulsions (seizures); psychosis; nerve abnormalities that cause strange sensations or alter muscular control or strength.

If an individual has several of these symptoms, the physician will then usually order a series of tests to examine how well the individual's immune system is functioning. In general, physicians look for evidence of autoantibodies. Although there is no one test that can definitely say whether or not a person has lupus, there are many laboratory tests which aid the physician in making a lupus diagnosis.

Routine clinical tests which suggest that the person has an active systemic disease include:

• sedimentation rate (ESR) and CRP (C-reactive protein) binding, both of which are frequently elevated in inflammation from any cause
• serum protein electrophoresis which may reveal increased gammaglobulin and decreased albumin
• routine blood counts which may reveal anemia and low platelet and white cell counts
• routine chemistry panels which may reveal
  • kidney involvement by increases in serum blood urea nitrogen and creatinine
  • abnormalities of liver function tests
  • increased muscle enzymes (such as CPK) if muscle involvement is present.

These kinds of abnormalities alert the doctor to the presence of a systemic disease with multiple organ involvement.