Lupus band test

An article about the Lupus band test, a diagnostic test for lupus erythematosus

Lupus Band Test

The Lupus band test is a diagnostic test used in the evaluation of systemic lupus erythematosus (SLE) and discoid lupus erythematosus (DLE). It involves the detection of immunoglobulin and complement deposits at the dermal-epidermal junction in skin biopsy specimens.

Lupus band test showing immunofluorescence at the dermal-epidermal junction

Procedure

The test is performed by obtaining a skin biopsy from a patient suspected of having lupus. The biopsy is typically taken from both sun-exposed and non-sun-exposed skin. The specimen is then subjected to direct immunofluorescence microscopy to detect the presence of immunoglobulins such as IgG, IgA, IgM, and complement components like C3.

Interpretation

A positive lupus band test is indicated by the presence of a band of immunoglobulin and complement deposits at the dermal-epidermal junction. In patients with systemic lupus erythematosus, the test is often positive in both sun-exposed and non-sun-exposed skin. In contrast, in discoid lupus erythematosus, the test is usually positive only in sun-exposed skin.

Clinical Significance

The lupus band test is a useful tool in the diagnosis of lupus erythematosus, particularly in distinguishing between systemic and discoid forms of the disease. However, it is not definitive on its own and must be interpreted in conjunction with clinical findings and other laboratory tests.

Limitations

The lupus band test has limitations, including false positives and negatives. It may be positive in other conditions such as dermatomyositis and lichen planus. Additionally, the test requires expertise in immunofluorescence microscopy and interpretation.

Related pages

• Systemic lupus erythematosus
• Discoid lupus erythematosus
• Direct immunofluorescence
• Skin biopsy