T4 ELISA Test kit




Free T4 ELISA kit Intended Use
Free T4 ELISA test kit is designed for the quantitative determination of Free Thyroxine (T4) Concentration in human serum.




Free T4 ELISA kit Components:
• Human Serum References
• fT4- Enzyme Reagent
• Antibody Coated Microplate
• Wash Solution Concentrate
• Substrate A
• Substrate B
• Stop Solution
• Product Instructions




Test Method Principle
This Diagnostic Automation/ Cortez Diagnostics Inc. Free T4 Enzyme Immunoassay (EIA) test is based on the principle of competitive immunoassay. Upon mixing immobilized antibody, enzyme-T4 conjugate and a serum containing the native free T4, a competition reaction results between the T4 free antigen and the enzyme-T4 conjugate for a limited number of insolubilized binding sites. For additional information and details please refer to the instructions for use.




Background Information
T4, the principal thyroid hormone, circulates in blood almost completely bound to carrier proteins. The main carrier is thyroxine-binding globulin (TBG). However, only the free or unbound portion of T4 has biological activity. The concentrations of the carrier proteins are altered in many clinical conditions, such as pregnancy, genetic predisposition, oral contraceptives and estrogen therapy. In normal thyroid function as the concentrations of the carrier proteins alters, the total T4 level changes so that the free T4 concentration remains constant. Thus, measurements of free T4 concentrations correlate better with clinical status than total thyroxine levels. The increase in total T4 associated with pregnancy, oral contraceptives and estrogen therapy occasionally result in total T4 levels over the limits of normal while the free T4 concentration remains in the normal reference range. Masking of abnormal thyroid function can also occur in both hyper and hypothyroid conditions by alterations in the TBG concentration. The total T4 can be elevated or lowered by TBG changes such that the normal reference levels result. The free T4 concentration can help in uncovering the patient’s actual clinical status.



Diagnostic Automation/ Cortez Diagnostics Inc. also provide other thyroid kits: T3 ELISA kit, T4 ELISA kit, TSH ELISA kit, TSH Ultra-sensitive ELISA kit, Free T3 ELISA kit, Free T4 ELISA kit and T Uptake ELISA kit. For more information about ELISA Kits, Rapid Tests, IFA Kits, CLIA Test Kits, or Serology tests, please see our website home page, or contact our Customer Service Representatives at 818-591-3030.