Methodology
We searched PubMed and Google Scholar for eligible publications and articles published before April, 2020 using the following search strategy. We used one of the following terms: “thyroid function test”, “thyroid assay”, “thyroid stimulating hormone”, “thyroxine”, “tri-iodothyronine”, “thyroid binding globulin”, “thyroid binding proteins” in combination with “drugs”, “medications”, “assay interference”, “biotin”, “heparin”, “oral contraceptive pills ”, “selective estrogen receptor modulators”, “estrogen”, “tamoxifen”, “raloxifene”, “droloxifene”, “fluorouracil”, “clofibrate”, “heroin”, “methadone”, “mitotane”, “nicotinic acid”, “asparaginase”, “glucocorticoids”, “androgens”, “anabolic steroids”, “l-asparaginase”, “salicylates”, “aspirin”, “salsalate”, “non-steroidal anti-inflammatory drugs”, “frusemide”, “phenytoin” and “carbamazepine”. References obtained from original papers were also scrutinized and included wherever relevant to the subject of this review.