Lower accuracy of testosterone, cortisol, and free T4 measurements using automated immunoassays in people undergoing hemodialysis

OBJECTIVES

Hormone measurements using automated immunoassays (IAs) can be affected by the sample matrix. Liquid chromatography tandem-mass spectrometry (LC-MS/MS) is less affected by these matrix effects. In clinical laboratories, testosterone, cortisol and, free thyroxine (FT4) are often measured using IAs. Renal failure alters serum composition in blood samples from people undergoing hemodialysis (HDp) and have, therefore, a complex serum constitution compared to healthy controls (HC). The goal of this study was to investigate the accuracy of testosterone, cortisol, and FT4 measurements in samples of HDp and to get more insight in the interfering factors.

METHODS

Thirty serum samples from HDp and HC were collected to measure testosterone, cortisol, and FT4 using a well standardized isotope dilution (ID)-LC-MS/MS method and 5 commercially available automated IAs (Alinity, Atellica, Cobas, Lumipulse, UniCel DXI). Method comparisons between LC-MS/MS and IAs were performed using both HDp and HC samples.

RESULTS

Average bias from the LC-MS/MS was for testosterone, cortisol, and FT4 immunoassays respectively up to 92, 7-47 and 16-27% more in HDp than in HC samples and was IA dependent. FT4 IA results were falsely decreased in HDp samples, whereas cortisol and testosterone concentrations in females were predominantly falsely increased. Correlation coefficients between LC-MS/MS and IA results were lower in HDp compared to HC samples.

CONCLUSIONS

Several IAs for testosterone (in women), cortisol, and FT4 are less reliable in the altered serum matrix of samples of HDp than in HC. Medical and laboratory specialists should be aware of these pitfalls in this specific population.

Improving Science by Overcoming Laboratory Pitfalls With Hormone Measurements

Despite all the effort taken, there is often surprisingly little attention paid to the hormone analyses involved in research studies. Thinking carefully about the quality of the hormone measurements in these studies is, however, of major importance, as this attention to methods may prevent false conclusions and inappropriate follow-up studies. We discuss issues regarding hormone measurements that one should consider, ideally prior to starting, or otherwise, as they arise during a scientific study: quality of the technique, expertise, matrices, timing and storage conditions, freeze-thaw cycles, lot-to-lot and day-to-day variation, analyses per batch or sample-wise, singlicate or duplicate measurements, combining methods, and standardization. This article and the examples mentioned herein aim to clarify the need to pay attention to the hormone analyses, and to help in making decisions. In addition, these examples help editors and reviewers of scientific journals to pay attention to the methods section in the submitted manuscripts and ask the right critical questions when needed.

Nutritional programming by glucocorticoids in breast milk: Targets, mechanisms and possible implications

Vertical transmission of glucocorticoids via breast milk might pose a mechanism through which lactating women could prepare their infants for the postnatal environment. The primary source of breast-milk glucocorticoids is probably the systemic circulation. Research from our group showed that milk cortisol and cortisone concentrations follow the diurnal rhythm of maternal hypothalamus-pituitary-adrenal axis activity, with a higher abundance of cortisone compared to cortisol. Measurement of breast-milk glucocorticoid concentrations is challenging due to possible cross-reactivity with progestagens and sex steroids, which are severely elevated during pregnancy and after parturition. This requires precise methods that are not hindered by cross reactivity, such as LC-MS/MS. There are some data suggesting that breast-milk glucocorticoids could promote intestinal maturation, either locally or after absorption into the systemic circulation. Breast-milk glucocorticoids might also have an effect on the intestinal microbiome, although this has not been studied thus far. Findings from studies investigating the systemic effects of breast-milk glucocorticoids are difficult to interpret, since none took the diurnal rhythm of glucocorticoids in breast milk into consideration, and various analytical methods were used. Nevertheless, glucocorticoids in breast milk might offer a novel potential pathway for signal transmission from mothers to their infants.