Congenital Hypotyroidism (CH) (TSH)

The NEONATAL TSH Screening ELISA is a sandwich ELISA in which two monoclonal anti-TSH antibodies recognize native TSH in the blood specimen. The reduction of 3.3’-5.5’-tetramethylbenzidine (TMB) by Horseradish Peroxidase (HRP)-labelled detection antibody will generate an absorbance signal. The measured absorbance signal intensity is proportional to the concentration of TSH in the test sample.

Congenital hypothyroidism in newborns is defined as a deficiency of thyroid hormones present at birth. It is one of the most common preventable causes of intellectual disability worldwide.
What causes hypothyroidism in newborns is an abnormal development of the thyroid gland in about 85% of cases, or by a disorder of thyroid hormone biosynthesis in 10-15% of cases. These disorders cause primary hypothyroidism with high concentrations of thyroid stimulating hormone (TSH) and low levels of thyroxine (T4). Secondary hypothyroidism, or central hypothyroidism, is rarer and results from TSH deficiency. However, peripheral congenital hypothyroidism is due to an abnormality in the transport, metabolism, or action of thyroid hormones.
There are also forms of transient congenital hypothyroidism, most often affecting premature children. These transient forms usually resolve spontaneously within months or years.

Thyroid hormones play a key role in psychomotor development and growth, in the body’s thermoregulation process, in maintaining muscle tone, or in bowel movements.
Symptoms of congenital hypothyroidism in newborns are often absent, although some are mildly hypotonic and sleep more. Specific symptoms often appear only after several weeks. They include difficulty in sucking, constipation, prolonged jaundice, myxedematous facies and macroglossia,abdominal distension with umbilical hernia and hypotonia. Slowed growth and delayed psychomotor development are usually apparent.