A doctor performs a physical examination, a review of the patient’s symptoms and multiple tests, such as blood, urinalysis and imaging studies, to diagnose lupus, according to Mayo Clinic. Lupus diagnoses are difficult, since the symptoms of lupus often mimic those of other conditions and vary widely between people.
Doctors must rely on multiple tests during the diagnostic process for lupus, notes Mayo Clinic. Lupus may cause a low white blood cell count or a low platelet count, which are measurable on a complete blood count test. An erythrocyte sedimentation rate test looks for elevated settling of red blood cells in a test tube, which may indicate lupus. Because lupus may affect the kidneys and liver, these organs are tested as well. Urine tests are conducted to look for elevated red blood cells or protein in the urine.
During the process of diagnosis, a doctor may order an antinuclear antibody, or ANA, test to look for the presence of antibodies produced by a stimulated immune system, notes Mayo Clinic. A positive ANA test may indicate lupus.
Imaging studies, such as chest X-rays and echocardiograms, are also useful in diagnosing lupus that affects the heart or lungs, advises Mayo Clinic. If lupus has damaged the kidneys, a kidney biopsy is part of diagnosis.