Semiquantitative result of IgG class antibodies
1 - 3 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Serum
1 mL
0.5 mL (Note: This volume does not allow for repeat testing.)
Red-top tube or gel-barrier tube
Room temperature
Temperature
Period
14 days
Refrigerated
Frozen
Freeze/thaw cycles
Stable x3
Hemolysis; icterus; lipemia; bacterial contamination
Aids in the diagnosis of Sjögren's syndrome (especially with vasculitis) and lupus patients with Sjögren's overlap syndrome.
Multiplex flow immunoassay
0.0-0.9 AI
SS-A(Ro) is found in 60% to 70% of patients with Sjögren's syndrome and 30% to 40% of patients with SLE. SS-B(La) is found in 50% to 60% of Sjögren's syndrome and 10% to 15% of SLE. SS-A cannot be demonstrated by immunofluorescence (it is soluble in the buffers used), but SS-B may be seen as a speckled antinuclear pattern. SS-A and SS-B are particularly useful in “ANA-negative” cases of SLE, being present in a majority of such cases. Patients who are ANA-positive and who have SS-A but not SS-B are very likely to have nephritis. Antibodies to SS-A are also associated with HLA loci DR3 and DR2 and with hereditary deficiency of C2. Anti-SS-A and anti-SS-B are found in virtually all children with neonatal lupus. Patients with SS-A may also have antibodies to cardiolipin, lupus anticoagulant, and clinical thromboses. This has been termed antiphospholipid antibody syndrome.