Hormone Assay Interference

Interference in immunoassay is a well recognised problem. This may be due to a number of factors such as non-specificity of antibodies used in the assay method or Interference from a component in the patient sample such as circulating antibodies. These interfering antibodies are specific to an individual patient and have the potential to interfere in an unpredictable way. The reported prevalence of such interfering antibodies varies from 0.05 to more than 2%.  Our experience with thyroid hormones and gonadotrophins is that interference occurs in approximately 0.5% clinical samples.

The approach to detection of interference that we have taken is:

1: alertness to the problem

2: to use an alternative analytical method either a different immunoassay method, or by organic extraction prior to analysis or by mass spectrometry.

3: to use PEG precipitation to remove interfering proteins

4: to use commercially available anti-animal antibody coated tubes to remove any endogenous antibody


Ismail AAA, J.H.Barth JH, Walker PL, Cawood M. Interference in immunoassay is an underestimated problem. Ann Clin Biochem 2002;39:366-373

Ismail AAA, Walker PL, Barth JH, Lewandowski KC, Jones RG, Burr WA. Wrong biochemistry results: two case reports and observational study in 5310 patients on potentially misleading thyroid-stimulating hormone and gonadotropin immunoassay results. Clin Chem 2002;48:2023-2029

Ismail AAA, Walker PL, Fahie-Wilson MN, Jassam N, Barth JH. Prolactin and macroprolactin: a case report of hyperprolactinaemia highlighting the interpretation of discrepant results. Ann Clin Biochem 2003;40:298-300

Page updated: 21/02/17 | Updated by: Dr. Julian Barth