SS-A Ab ELISA Kit (Sjögren Syndrome Type A)

Full Name: SS-A Ab ELISA Kit (Sjögren Syndrome Type A)
Reactivity: Human
Sample Type: Plasma, Serum
Sensitivity: 1.0 U/ml

BACKGROUND

Sjögren syndrome type A antigen (SS-A) are autoantibodies that are regarded as antinuclear antibody (ANA) which essentially targeting the nucleic acids in the cell cytoplasm rather than the cell nucleus. This is in contrast to standard ANAs which tend to target nucleic acids in the cell nucleus, for this reason individuals having ANA-negative systemic lupus are found to frequently have anti-SSA antibodies.

Anti-SSA antibodies are vital diagnostic markers which can be used to diagnose many autoimmune diseases for example SLE, PSS and polymyositis. Clinical studies have also indicated that over 70 percent patients with SS-A antibodies also display rheumatoid factor (RF). This is an autoantibody that can target immunoglobulin G, which is present in rheumatoid arthritis (RA), Sjogren’s syndrome scleroderma and polymyositis.

INTENDED USE

Human SS-A Ab ELISA kit is a method intended for in-vitro quantitative detection of IgG auto-antibodies to Sjögren syndrome type A (SS-A antibody, anti-SSA, SS-A Ab) in human serum or plasma. This assay has a minimum analytical sensitivity limit of 1.0 U/ml.

CONTENT

All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

Divisible Microplate: Consisting of 12 modules of 8 wells, highly purified SS-A (52 and 60 kDa) antibodies bound to microwells.
Calibrators (A-F): Concentration 0-200 U/ml, made up from SS-A antibody.
Controls Positive and Control Negative: Containing human anti-SSA.
Sample Buffer (5x).
Enzyme Conjugate: Contains anti-human IgG antibodies, HRP labelled.
TMB Substrate.
Stop Solution: Contains acid.
Wash Buffer (50x Concentrated).
Instruction Manual.
Certificate of Analysis.

SENSITIVITY

The minimum detection sensitivity level of Sjögren syndrome type A (anti-SSA antibodies, SS-A Ab) IgG auto-antibodies using current SS-A antibody ELISA kit was 1.0 U/ml. The dynamic range for this assay is 12.5 – 200.0 U/ml.

ASSAY CHARACTERISTICS

– Measuring Range: 0 – 200 U/ml
– Linearity: 97 – 100%
– Intra Assay Precision: 2.7 – 3.6%
– Inter Assay Precision: 1.1 – 6.4%
– Limit Of Detection (LOD): 1 U/ml.
– Expected Values: Cut-off 25 U/ml.
– Results Interpretation: Negative: < 15 U/ml, Borderline 15-25 U/ml, Positive: ≥ 25 U/ml.
– Interference: None.
– Clinical Diagnosis: Sensitivity (72.9%), Specificity (93.0%), Overall agreement (84.7%).

REFERENCES

A comprehensive review of autoantibodies in primary Sjögren’s syndrome: clinical phenotypes and regulatory mechanisms. J Autoimmun. (2014) 51: 67-74. Review. Kyriakidis N.C., et al.
Biologic treatment in Sjögren’s-syndrome. Rheumatology (Oxford). (2015) 54 (2): 219-30. Review. Sada P.R., et al.
Clinical characteristics of RA patients with secondary SS and association with joint damage. Rheumatology (Oxford). (2015) 54 (5): 816-20. Brown L.E., et al.
SS-A (Ro) antibody in random mother-infant pairs. J Clin Pathol. (1985) 38 (1): 73-5. Calmes M. and Bartholomew B.A.
Anti-Ro(SSA) antibodies in patients with rheumatoid arthritis–a possible marker for gold induced side effects. J Rheumatol. (1994) 21 (6): 1040-2. Tishler M., et al.

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