Immunoreactive LH in long‐term frozen human urine samples

Abstract

Urine provides a convenient non-invasive alternative to blood sampling for measurement of certain hormones. Urinary luteinizing hormone (LH) measurements have been used for endocrinology research and anti-doping testing. However, the commercially available LH immunoassays are developed and validated for human blood samples but not urine so that LH assays intended for use with urine samples need thorough validation. Therefore, the present study evaluated the measurement of urinary LH immunoreactivity using previously validated immunofluorometric (IF) and immunochemiluminometric (ICL) LH assays after prolonged frozen storage. LH was measured in serial urine samples following administration of a single injection of one of two doses of recombinant human chorionic hormone (rhCG) with assays run at the end of study (2008) and again after four years of frozen (-20 °C) storage where samples were stored without adding preservatives. The ICL assay showed quantitatively reproducible LH measurements after prolonged -20 °C storage. However, the IF immunoassay gave consistently lower LH levels relative to ICL (2008) with a further proportionate reduction after four years of sample storage (2012). Yet, both the assays displayed similar patterns of the time-course of urine LH measurement both before and after four years of frozen storage. In conclusion, we found that both immunoassays are suitable for urinary LH measurements with ICL assay being more robust for quantitative urinary LH measurement such as for anti-doping purposes, whereas the IF could be applicable for research studies where urine LH levels are compared within-study but not in absolute terms.

First Morning Voided Urinary Gonadotropin Measurements as an Alternative to the GnRH Test

“…There are also differences in the detection limits for LH, and a reliable estimation of low prepubertal levels requires the use of a highly sensitive assay. The stability of LH in urine is also a problem if urinary samples are stored frozen; much of the LH can be degraded during long-term storage of urine at -20°C [18,33]. When interpreting the results of this study, it is important to note that the results are based on subjects referred for investigation of different growth and pubertal disorders.…”

“…Different assays recognize this fragment to variable degrees, and therefore the measured LH concentrations are highly dependent on the assay used [33]. There are also differences in the detection limits for LH, and a reliable estimation of low prepubertal levels requires the use of a highly sensitive assay.…”

Impaired receptivity and decidualization in DHEA-induced PCOS mice

“…DHEA is one of the most abundant circulating androgens in PCOS patients26. DHEA-induced PCOS model has been established in different mouse strains (Parkes strain mice27, BALB/c mice28, C57BL/6 mice23 and FVB/NJ mice29). …”

Androgens

“…Whether additional knowledge of the UGT2B17 genotype is useful beyond the T/E ratio phenotype remains to be defined [78] . An alternative or corroborative marker for the administration of any exogenous androgen is the urine T/LH ratio [63,64,81] ; however, this measure depends on the validity of urine LH measurements by immunoassays which are validated solely for human serum samples so that they suffer from method-specific bias and only a few are valid for human urine measurements [82] .…”