IMMULITE 2000/2000 XPi TSI Assay

Graves’ disease (GD) is an autoimmune disorder caused by the presence of thyroid stimulating immunoglobulins (TSI) that bind to the TSH receptor on the thyroid cells and stimulate the uncontrolled production of thyroid hormones. Detecting the presence of TSI in the blood is a powerful diagnostic tool for the differential diagnosis of GD.

TSI measurements are also used to monitor the response to GD therapy and prediction of remission or relapse, confirming Graves’ ophthalmopathy, and for predicting neonatal thyroid hyperthyroidism.^1,2 Incorporating the TSI assay into existing diagnostic algorithms has been shown to reduce overall direct costs of GD diagnosis by up to 43%, with the net cost of avoiding misdiagnosis reduced by up to 85%.³

The IMMULITE® 2000/2000 XPi TSI assay is the first automated and quantitative TSI assay available today. TSH receptor antibody (TRAb) assays detect both thyroid blocking and stimulating antibodies. However, blocking antibodies inhibit TSH stimulation of thyroid cells and lead to hypothyroidism. The IMMULITE 2000/2000 XPi TSI assay detects thyroid stimulating antibodies, the specific cause of GD pathology, with a clinical sensitivity and specificity of 98.6% and 98.5% respectively. With a 65-minute total assay time and ready-to-use, stable reagents, the use of this assay can make the differential diagnosis of GD faster and easier, allowing patients to be diagnosed and treated sooner.

If you are interested in adding TSI testing to your IMMULITE 2000 or 2000 XPi system menu, please contact the Inside Sales Department at (800) 242-3233, option 3.

Assay Specifications

IMMULITE 2000 TSI Assay

Sample Type	Serum, Plasma (Li Heparin, EDTA)
Sample Volume	50 µL
Assay Range	0.10 – 40 IU/L
Limit of Quantitation	0.10 IU/L
Calibration Interval	4 weeks
Onboard Stability	90 days
Time to First Result	65 minutes
Clinical Sensitivity	98.3%
Clinical Specificity	99.7%

Traceable to the WHO 2nd International Standard NIBSC 08/204

If you are interested in adding TSI testing to your IMMULITE 2000 or 2000 XPi system menu, please contact the Inside Sales Department at (800) 242-3233, option 3.

Understanding Graves' Disease

Graves’ disease is an autoimmune disorder that leads to overactivity of the thyroid gland – hyperthyroidism. It is caused by an abnormal immune system response that causes the thyroid gland to produce too much thyroid hormone. The thyroid gland is a butterfly-shaped organ that lies flat against the windpipe in the throat. It produces the hormones thyroxine (T4) and triiodothyronine (T3) and plays an important role in controlling the body's metabolism.¹

Video: Diagnosing Graves' Disease with TSI Testing

What are the symptoms of Graves’ disease?²
People with Graves’ disease may have common symptoms of hyperthyroidism such as

nervousness or irritability
fatigue or muscle weakness
heat intolerance
trouble sleeping
hand tremors
rapid and irregular heartbeat
frequent bowel movements or diarrhea
weight loss
goiter, which is an enlarged thyroid that may cause the neck to look swollen and can interfere with normal breathing and swallowing

In addition, the eyes of people with Graves’ disease may appear enlarged because their eyelids are retracted—seem pulled back into the eye sockets—and their eyes bulge out from the eye sockets. This condition is called Graves’ ophthalmopathy.²

Who is likely to develop Graves’ disease?

Graves’ disease usually occurs in people younger than age 40 and is seven to eight times more common in women than men.² Women are most often affected between ages 30 and 60.²
According to the National Women's Health Information Center, Graves’ disease affects about 2% of women at some time in their lives.

Read more about women and thyroid disease

Factors such as age, sex, heredity, and emotional and environmental stress are likely involved in Graves’ disease. And a person’s chance of developing Graves’ disease increases if other family members have the disease. Researchers have not been able to find a specific gene that causes the disease to be passed from parent to child. While scientists know some people inherit an immune system that can make antibodies against healthy cells, predicting who will be affected is difficult. ²

Laboratory Testing
Laboratory testing is essential to verify the diagnosis, help estimate the severity of, monitoring, and assisting in planning therapy for Graves’ disease patients.
To detect thyroid dysfunction, testing may begin with:

TSH — typically low in Graves’ disease
Total or free T4 — usually elevated
Total or free T3 — often elevated

The above tests may also be ordered periodically to monitor thyroid function and hormone production.

Laboratory tests used to help diagnose Graves’ disease and distinguish it from other autoimmune conditions may include one or more tests used to detect the presence of thyroid antibodies:¹

Thyroid stimulating immunoglobulin (TSI) — the presence of this antibody is diagnostic for Graves’ disease.
Thyroid stimulating hormone receptor antibody (TRAb) — less specific than TSI
Anti-thyroid peroxidase antibody (anti-TPO) — this autoantibody is found in most people with Graves’ disease, as well as in Hashimoto thyroiditis.

If you are interested in adding TSI testing to your IMMULITE 2000 or 2000 XPi system menu, please contact the Inside Sales Department at (800) 242-3233, option 3.

Services & Support

Education & Training

Did this information help you?

Gupta, Manjula K. Thyrotropin-receptor antibodies in thyroid diseases: advances in detection techniques and clinical applications. Clinica Chimica Acta. 2000;293:1-29

M.R. Bjorgaas, H. Farstad, S.C. Christiansen, H-G.K. Blaas. Impact of thyrotrophin receptor antibody levels on fetal development in two successive pregnancies in a woman with Graves’ disease. Horm, res. Paediatr. 79:39-43, 2012.

McKee A., Peyerl, F. TSI assay utilization: impact on costs of Graves’ hyperthyroidism diagnosis. AJMC. 2012; 18(1):1-15.

http://labtestsonline.org/understanding/conditions/graves/

http://www.endocrine.niddk.nih.gov/pubs/graves/

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