Interference in free thyroxine immunoassay.
case_report · Level V
Where this comes from
- Record sourced from PubMed, PMID 18395170.
- Also identified by DOI 10.1016/j.ejim.2007.05.009.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
We report two patients who presented with non-specific symptoms of tiredness that prompted their clinician to order a thyroid function test. In both cases, free thyroxine (T4) was reported to be high, with a normal thyroid-stimulating hormone (TSH). Repeated blood tests from the same laboratory using the same assay method yielded similar results. Due to discrepancies between the clinical and laboratory findings, we decided to repeat the blood tests at another laboratory using a different assay method. This revealed normal free T4 and TSH levels, suggesting that heterophile antibodies were interfering with the free T4 assay, leading to clinical confusion.