Falsely elevated serum oestradiol due to exemestane therapy

Falsely elevated troponin levels.

To diagnose a myocardial infarction, an increase and/or fall in troponin values by at least one value > the 99th percentile in a healthy reference population is required, combined with other ischaemic signs or symptoms (1). Troponin T and troponin I are considered equal in diagnostics of myocardial infarction. There is only one manufacturer of tests for troponin T and thus only one reference ra...

Falsely Elevated Steroid Hormones in a Postmenopausal Woman Due to Laboratory Interference

Laboratory interference is a drawback in hormonal testing, and clinicians should have a high index of suspicion when faced with biochemical results discordant with the patient's clinical manifestations. A 62-year-old postmenopausal woman initially consulted her primary care physician for mood lability; laboratory workup showed markedly elevated levels of total serum estradiol, progesterone, tes...

Falsely elevated thyroid-stimulating hormone (TSH) level due to macro-TSH.

We encountered a 60-year-old woman with remarkably elevated thyroid-stimulating hormone (TSH) level as measured by electrochemiluminescent immunoassay (ECLIA), but with no specific symptoms, and with normal levels of free T3 and free T4. We performed the following investigations: polyethylene glycol (PEG) precipitation test, human antimouse IgG antibody (HAMA) interference test, and 3 additiona...

Falsely increased values for serum creatinine during therapy with cefoxitin.

Falsely elevated prothrombin international normalized ratio values.

International normalized ratio (INR) monitoring is essential during oral anticoagulation therapy to minimize bleeding complications and thrombotic events. Laboratory technicians cannot differentiate falsely elevated INR results due to problems in drawing blood from truly elevated INR values, but the extent of this phenomenon is unclear. We determined the proportion of patients with INR values o...