Biological variation of immunological blood biomarkers in healthy individuals and quality goals for biomarker tests.

Background: Cytokines, chemokines, adipocytokines, soluble cell receptors, and immune activation markers play an important role in immune responsiveness and can provide prognostic value since they reflect underlying conditions and disease states. This study was undertaken to investigate the components of biological variation for various laboratory tests of blood immunological biomarkers.

Results: Estimates of intra-individual coefficient of variation (CV) and inter-individual coefficient of variation (CV) were examined for blood immunological biomarkers.

The influence of EDTA Vacutainer blood collection tube on the level of blood interleukin-1 receptor antagonist.

Background: The use of anticoagulants may influence the composition of blood cells and interfere with plasma levels of IL-1ra when unprocessed EDTA blood samples are stored for long periods of time.

Methods: Blood was drawn into EDTA and heparinized blood collection tubes from 11 HIV-1 negative men participating in the Multicenter AIDS Cohort Study (MACS) and 4 healthy volunteers. The blood was processed according to the experiments detailed in the method and after incubation; supernatants were collected and stored at -70 °C until batch testing using IL-1ra ELISA.

Urine reference intervals for human chorionic gonadotropin (hCG) isoforms by immunoextraction-tandem mass spectrometry to detect hCG use.

Human chorionic gonadotropin (hCG) stimulates testosterone production by the testicles and can normalize suppressed testosterone concentrations in males following prolonged anabolic steroid use. Because of the potential for abuse by males, hCG is on the World Anti-Doping Agency (WADA) list of prohibited substances. The majority of WADA-accredited laboratories measure urinary hCG using an automated immunoassay.

The influence of small doses of ethanol on the urinary testosterone to epitestosterone ratio in men and women.

Endogenous steroid use can increase urinary testosterone/epitestosterone (T/E) values. In addition, ethanol in amounts >0.5 g per kg of body weight (g/kg) can also increase T/E values.

Relationships of sex hormone levels with leukocyte telomere length in Black, Hispanic, and Asian/Pacific Islander postmenopausal women.

Background: Sex hormones may play important roles in sex-specific biological aging. In the study, we specifically examined associations between circulating sex hormone concentrations and leukocyte telomere length (TL).

Methods: A cross-sectional study was conducted among 1124 Black, 444 Hispanic, and 289 Asian/Pacific Islander women in the Women's Health Initiative Observational Cohort.