Family Nurse Practitioner Exam

Which laboratory test is commonly positive in systemic lupus erythematosus patients?

1. A) Rheumatoid factor

2. B) Antinuclear antibody (ANA)

3. C) Antiparietal antibody

4. D) Immunoglobulin

The correct answer is: B) Antinuclear antibody (ANA)

The presence of antinuclear antibodies (ANA) is commonly associated with systemic lupus erythematosus (SLE) and serves as an important laboratory marker for this condition. In SLE, the immune system produces these antibodies that target the body's own cells, indicating an autoimmune response. While a positive ANA test is not exclusive to lupus and can be found in other autoimmune diseases as well, it is notably frequent in those with SLE, making it a key element in the disease's diagnosis. The other tests listed, such as rheumatoid factor, are associated with other conditions like rheumatoid arthritis but are not specific to systemic lupus erythematosus. Antiparietal antibodies are generally related to pernicious anemia rather than lupus, and while immunoglobulin levels may be assessed in various contexts, they are not a primary marker for diagnosing systemic lupus erythematosus. This specificity and prevalence of positive ANA in SLE patients substantiate its significance in identifying the disease.