024
Test #
IgA Split Skin
CPT Code(s) #
88346
If Profile, Includes Tests:
N/A
Disease Name:
Linear IgA Bullous Dermatosis (LABD), Linear IgA, Chronic Bullous Dermatosis of Childhood (CBDC)
Type of Study:
Serum Studies
Methodology:
Indirect Immunofluorescence
Substrate:
Normal and Split Human Skin
Reference Range:
Negative: <1:5
Units:
Titer
Schedule:
Assay performed daily Monday-Friday. Report availability is within 48-72 hours from the time of specimen receipt.
Specimen Requirements:
Collect 2-5 ml of blood in a red top Vacutainer or serum separator (SST) tube, allow blood to clot, and centrifuge. Label tube appropriately.
Sample Stability:
Room temperature = stable during shipment
2ºC to 8ºC = 5 days
-25ºC to -15ºC = 1 year
Clinical Relevance:
Linear IgA Bullous Dermatosis (LABD) is a chronic, acquired, autoimmune blistering disease. It is characterized by subepidermal blistering and linear deposition of immunoglobulin A (IgA) basement membrane antibodies. The disease affects both children and adults. There are some differences in their clinical presentations, therefore the disease in children is termed as Chronic Bullous Disease of Childhood (CBDC). The immunopathology of LABD and CBDC is similar (Venning, 2011). IgA antibodies to BMZ of skin by IIF on split human skin can be detected in about 30% adult patients with LABD and in almost 75% children with CBDC. This test helps to differentiate the autoantibodies reacting on the epidermal roof of the split (target antigens are the shed ectodomains of BP180 molecule) from the antibodies reacting on the floor (target antigen is LAD285 and in rare cases type VII Collagen). Patients with LABD may have co-existing IgG antibodies, therefore IIF test for IgG and IgG4 antibodies on Split Human Skin (#014) should also be done. Vanessa A. Venning. Linear IgA Disease: Clinical Presentation, Diagnosis, and Pathogenesis. Dermatologic Clinics, 2011;29 (3): 453-458.
