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  1. Siemens Healthineers Brasil
  2. Doenças e Especialidades Clínicas
  3. Tireoide
  4. Disponível agora o Ensaio para TSI IMMULITE 2000/2000 XPi

Ensaio de TSI IMMULITE 2000/2000 XPi

A Doença de Graves (DG) é uma doença autoimune causada pela presença de imunoglobulinas estimulantes da tireoide (TSI) que se ligam aos receptores de TSH nas células da tireoide e estimulam a produção descontrolada de hormônios tireoidianos. A detecção da presença de TSI no sangue é uma ferramenta poderosa para o diagnóstico diferencial de DG.

As medidas de TSI também são usadas para monitorar a resposta à terapia para DG e na predição da remissão ou recidiva, na confirmação da oftalmopatia de Graves e na predição do hipertireoidismo neonatal.¹ ² A incorporação do ensaio de TSI aos algoritmos de diagnóstico existentes tem mostrado uma redução geral de custos diretos com o diagnóstico de DG de até 43%, com um custo líquido de evitar um diagnóstico errado reduzido em até 85%.³

O ensaio de TSI IMMULITE 2000/2000 XPi é o primeiro ensaio de TSI automatizado e quantitativo disponível atualmente. Os ensaios de anticorpo antirreceptor de TSH (TRAb) detectam tanto os anticorpos estimulantes da tireoide quanto os bloqueadores. Entretanto, os anticorpos bloqueadores inibem a estimulação das células da tireoide pelo TSH e levam ao hipotireoidismo. O ensaio de TSI IMMULITE 2000/2000 XPi detecta anticorpos estimulantes da tireoide, a causa específica da patologia da DG. Com um tempo total de ensaio de 65 minutos e reagentes prontos para o uso e estáveis, este ensaio pode tornar o diagnóstico diferencial da DG mais rápido e fácil, permitindo que os pacientes sejam diagnosticados e tratados mais cedo.

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

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

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.
 

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. 5

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:4

  • 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.
     
1
Gupta, Manjula K. Thyrotropin-receptor antibodies in thyroid diseases: advances in detection techniques and clinical applications. Clinica Chimica Acta. 2000;293:1-29
2
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.
3
McKee A., Peyerl, F. TSI assay utilization: impact on costs of Graves’ hyperthyroidism diagnosis. AJMC. 2012; 18(1):1-15.
4
http://labtestsonline.org/understanding/conditions/graves/
5
http://www.endocrine.niddk.nih.gov/pubs/graves/
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