Family Nurse Practitioner Exam

What laboratory test is most strongly associated with systemic lupus erythematosus (SLE)?

1. Sedimentation rate

2. C-reactive protein

3. Antinuclear antibody (ANA)

4. Systemic lupus erythematosus (SLE)

The correct answer is: Antinuclear antibody (ANA)

The most strongly associated laboratory test for systemic lupus erythematosus (SLE) is the antinuclear antibody (ANA) test. This test is significant because the presence of ANA is a hallmark of autoimmune conditions, particularly SLE. In SLE, a high proportion of patients (typically over 95%) will test positive for ANA, making it a key diagnostic marker. The ANA test detects a variety of autoantibodies that target the cell nucleus. While a positive ANA is not exclusive to SLE and can be found in other autoimmune diseases, the strong correlation between a positive ANA and the diagnosis of SLE makes it critically important in the initial assessment and diagnosis of this condition. Other tests, such as sedimentation rate and C-reactive protein, are more useful for assessing inflammation and disease activity rather than being specific indicators for SLE itself. Therefore, the antinuclear antibody test is uniquely associated with systemic lupus erythematosus, providing the most direct link to the disease.