What lab result is commonly used to support a diagnosis of SLE?

A positive antinuclear antibody (ANA) test is a critical laboratory finding commonly associated with systemic lupus erythematosus (SLE). ANAs are a group of autoantibodies that target substances within the nucleus of cells. While a positive ANA is not exclusive to SLE and can be seen in other autoimmune diseases, it is a key indicator when considered alongside clinical symptoms in the context of lupus.

This lab test helps clinicians in the diagnostic process, especially when the clinical presentation suggests SLE, such as if the patient is experiencing symptoms like joint pain, skin rashes, or renal involvement. Elevated ANA levels indicate an autoimmune response, which is a hallmark of SLE.

In contrast, while rheumatoid factor might be positive in rheumatoid arthritis and some cases of SLE, it is not diagnostic for lupus. Elevated liver enzymes can suggest liver involvement or damage, but they are not specific for lupus. Low hemoglobin levels can indicate anemia, which can occur in lupus patients, but this finding alone does not support a diagnosis of SLE. The ANA test is the most significant lab result that aligns closely with the diagnosis of systemic lupus erythematosus.