A doctor may use the phrase "borderline lupus" when symptoms or blood test results suggest lupus, but there is not enough information for a definite diagnosis. This occurs commonly because some of the blood tests used to evaluate lupus, such as the anti-nuclear antibody (ANA), can come back positive in people without lupus. In addition, some of the symptoms of lupus, such as joint pain, can occur from a variety of causes, and so are not specific to lupus. Doctors therefore must look for a combination of criteria from the blood tests, the medical history, and the physical examination to make an accurate diagnosis.
The most commonly used diagnostic criteria were established by the American College of Rheumatology. If a person meets 4 or more of the 11 criteria, then a diagnosis of lupus is likely. If a person meets fewer than the required number, a doctor may use a term such as "borderline lupus", "incomplete lupus" or "undifferentiated" disease. When this occurs, it is important to continue to follow up with your doctor for monitoring.
Studies suggest that a small percentage of people in this "borderline" group go on to develop additional symptoms or blood work findings and are eventually diagnosed with lupus or a related condition. This progression usually occurs within the first five years. However, most people never develop additional criteria.