Time-resolved enzyme immunoassay for the determination of thyrotropin in serum

✍ Scribed by R.C. Morton; A. Papanastasiou-Diamandi; E.P. Diamandis; M.J. Khosravi

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 112 KB
• Volume: 26
• Category: Article
• ISSN: 0009-9120
• DOI: 10.1016/0009-9120(93)90080-p

✦ Synopsis

TSH by the new assay and <0.1 mIU/L in the "TSHS" assay. This problematic group included a number of untreated Graves disease patients. This was a reproducible finding within samples and for the patient over time. Other patients who gave discordant TSH results with the new formulation included some on T4 replacement therapy and some receiving thyroid suppression therapy.

In conclusion we have demonstrated significant variance in results at low levels of TSH with the new BM TSH reagent. This appears to be due in part to a positive proportional bias but more importantly, to idiosyncratic differences related to the patients themselves. The original "TSHS" assay is not available and the new assay is in widespread use. Low TSH results from this assay must be viewed with caution. BM have identified several interfering substances, have altered the formulation of their kit, and are expected to release the improved reagent shortly.