Recently, nonisotopic (often automated) immunoassays for measuring serum free thyroxin (FT4) have become available. Though more costly then radioimmunoassays, they are considerably more convenient. We studied the influence of endogenous albumin and thyroxin-binding globulin concentration on five automated, nonisotopic methods of measuring FT4 (Enzymun on ES300 [one-step], Stratus I and II [one-and-a-half-step], Delfia [two-step], and IMx [two-step]). We observed that they (a) are influenced very little by endogenous serum binding proteins and (b) seem to have sufficient within-run precision to justify performing single measurements on patient specimens. Additional studies are now in progress to assess the diagnostic performance of FT4 methods based on the use of radiolabeled T4 or T4 analogs in patients with non-thyroidal illnesses.

Agency
National Institute of Health (NIH)
Institute
Clinical Center (CLC)
Type
Intramural Research (Z01)
Project #
1Z01CL010152-06
Application #
3837986
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
6
Fiscal Year
1992
Total Cost
Indirect Cost
Name
Clinical Center
Department
Type
DUNS #
City
State
Country
United States
Zip Code