Diagnosis starts with a blood test
One test cannot determine if someone has lupus or not. It needs several tests. Complicating matters further, lupus has many symptoms which are similar to other diseases. Also, these symptoms can start showing after weeks or months.
If lupus has to be diagnosed, then a doctor should find a laboratory or physical evidence of the condition. Such evidence includes skin biopsy, swelling of joints, fluid around the heart or lungs, or protein in the urine. The doctor will also have to go through the person’s medical history and another test to eliminate other diseases.
Most doctor’s use “Eleven Criteria of Lupus” that help in excluding other diseases and diagnose lupus. When the patient meets at least four of these criteria, then the patient is diagnosed with lupus.
An antinuclear antibody blood test is usually used to rule out lupus when the results come out negative. The test will also show positive results for anyone with lupus. However, in some cases, the results might be positive even with those people without lupus. If the results come back positive, then other criteria need to be examined.