Open AccessThyroid function testing evaluated on three immunoassay systems
Author(s) -
Christenson Robert H.,
Duh ShowHong,
Clarisse Diana E.,
Zorn Nancy
Publication year - 1995
Publication title -
journal of clinical laboratory analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 50
eISSN - 1098-2825
pISSN - 0887-8013
DOI - 10.1002/jcla.1860090306
Subject(s) - thyroid function tests , thyroid , thyroid function , medicine , immunoassay , endocrinology , chemistry , immunology , antibody
Total thyroxine (TT 4 ), tracer uptake, thyroid‐stimulating hormone (TSH), and free T 4 (FT 4 ) testing was examined in the ACS 180, Abbott IMx, and Stratus II systems. TSH sensitivity studies demonstrated that the ACS and IMx are second‐generation assays; the Stratus showed between first‐ and second‐generation performance. Except for one control below the detection limit, TSH imprecision was 3–10%. TSH accuracy was adequate for all systems. TT 4 imprecision was 4–7%, except for the lowest control with the Stratus (18%). TT 4 method agreement showed bias of about 20% between the systems. TT 4 accuracy was compromised at the low end for the Stratus II, but was satisfactory otherwise. FT 4 imprecision was 20% for the Stratus, <5% for the IMx and 6% for the ACS. Uptake assays showed imprecision of 5–10%. The laboratory diagnosis indicated by each system's FT 4 and calculated FT 4 Index results were compared to determine diagnostic accuracy. In routine specimens, different clinical classifications were observed for 25% of specimens with the ACS, 19% with the Stratus, and 7% with the IMx; in the altered protein group, the Stratus showed 9% discordant results, the ACS showed 3%, and the IMx 0%. Of the three systems examined here, the Abbott IMx system showed the best overall performance.©1995 wiley‐Liss, inc.