Thyretain TSI Reporter BioAssay test for detecting auto-antibodies attains the FDA clearance

Aug 25 2009

Diagnostic HYBRIDS announces the FDA clearance, for marketing under the 510(k) pre-notification process, of the Thyretain TSI Reporter BioAssay. Thyretain is an in vitro diagnostic use test that specifically detects auto-antibodies called thyroid stimulating immunoglobulins (TSI) in patient serum. Thyretain is the first FDA-cleared test that specifically detects TSI and is to be used as an aid in the differential diagnosis of Graves’ disease, an autoimmune thyroid disorder. The Thyretain TSI Reporter BioAssay Kit is available for commercial use after a recently completed, 2-phase multi-site, clinical trial of the product in nearly 600 patients.

Graves’ disease is characterized by the presence of TSI in the bloodstream which results in over-stimulation of the thyroid gland and low thyroid stimulating hormone (TSH) levels, a condition known as hyperthyroidism. Eighty percent of Graves’ disease cases occur in women, and can be difficult to diagnose because symptoms vary greatly and often mimic other illnesses.

“Initial symptoms for thyroid disorders can often be nonspecific,” said Dr Frank L. Schwartz, MD. “By finding TSI’s in patient serum, Thyretain is a rapid and reliable bioassay that provides a definitive assessment that could lead to earlier diagnosis of Graves’ disease and better patient management.” Dr Schwartz is Professor of Endocrinology and J.O. Watson Chair for Diabetes Research and Director of the ARHI Diabetes Center at the Ohio University College of Osteopathic Medicine.

Thyretain provides laboratories with the ability to test for TSI using standard laboratory equipment, and unlike other non-specific thyroid-related assays, does not require the use of radioactivity and eliminates ambiguity of test results that can be confounded by the presence of non-TSI auto-antibodies. The kit includes a genetically-engineered cell line that produces the reporter enzyme luciferase in response to specific TSI binding and the amount of luciferase produced is then rapidly detected using a luminometer.

“When used earlier when hyperthyroidism is first suspected, this assay may provide primary care physicians and patients alike reliable diagnostic information when classic symptoms of goiter or thyroid-related eye disease (ophthalmopathy) are absent,” said Jeff Houtz, Senior Product Manager for Thyretain. Houtz further noted that earlier diagnosis of Graves’ disease may lead to an increased awareness and consideration of medical therapy before a decision to radio-ablate the patient’s thyroid is chosen.

Graves’ disease affects 1-2% of the population, and mostly appears in women in their forties. Thyretain will enable physicians to detect TSI in the bloodstream and assist them in confirming the diagnosis of Graves’ disease sooner than with standard thyroid test panels only.

According to Elaine Moore, MT (ASCP), “this new bio-assay for TSI from Diagnostic Hybrids offers greater specificity as it only detects the TSI present in a patient’s serum, aiding in a more accurate early diagnosis of Graves’ disease, and with further studies may be shown useful for evaluating the patient's response to therapy, and predicting remission from disease.” Moore is a Graves’ disease patient and author of “Graves’ Disease, A Practical Guide.”

The Thyretain TSI Reporter BioAssay will be made available through major commercial reference laboratories in the U.S., and in select hospital systems, within forty-five days.

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