Quantitation of urinary gonadotropins in normal children

Moderate Day-To-Day Variation in First-Morning Urine Total Luteinizing Hormone Levels Supports the Use of a Single Determination to Identify Imminent Puberty

OBJECTIVES

We aimed to study the daily variation in first-morning urinary total luteinizing hormone (U-LH) determination and validate it as a noninvasive method for analyzing age- and pubertal stage-related changes in LH immunoreactivity (LH-ir) levels to predict imminent onset of central puberty.

METHODS

We determined three consecutive first-morning total U-LH along with spot serum LH and follicle-stimulating hormone concentrations in 354 children (160 boys aged 2.8-17.8 yr and 194 girls aged 2.6-18.0 yr) with known pubertal stages. The samples were analyzed using an immunofluorometric assay (Delfia, PerkinElmer, Finland). The net day-to-day variation (net CV%) in U-LH-ir levels was calculated by subtracting the inter-assay CV% of the assay reported by the manufacturer from the gross inter-assay CV% calculated from three consecutive samples. U-LH-ir levels were classified as prepubertal (< 0.60 IU/L), highly likely pubertal (0.60-0.99 IU/L), and pubertal (≥ 1.00 IU/L).

RESULTS

On average, the gross and net inter-assay CV% values for different U-LH concentrations measured on three consecutive mornings were 37.6% and 32.7%, respectively. Despite this level of day-to-day variation, only 3.6% of the test results for boys and 4.9% for girls were inconsistent in classifying total U-LH-ir levels as prepubertal, peripubertal, or pubertal. Our results showed that the activation of the hypothalamo-pituitary-gonadal hormone axis, which signals the onset of puberty, occurs at a similar age in both boys and girls, confirming our earlier findings that the timing of this process is independent of sex. Further, our findings confirmed that the onset of pubertal gonadotropin secretion in boys occurs already at a testicular volume of 1 to 2 mL, well before clear clinical signs of puberty.

CONCLUSIONS

A single first-morning total U-LH measurement appears to be a valid clinical test for classifying children or adolescents into prepubertal, peripubertal, and pubertal groups. This study validates the recently reported finding that the timing of central puberty onset is sex-independent. The duration between the initial activation of gonadotropin secretion and the first clinical signs of puberty was longer in boys than in girls.

Critical appraisal of diagnostic laboratory tests in the evaluation of central precocious puberty

Pubertal onset is characterized by reactivation of the hypothalamic-pituitary-gonadal axis resulting in pulsatile gonadotropin secretion and subsequent sex steroid production. Accurate measurements of the gonadotropins and sex steroids are essential to ensure timely diagnosis of precocious puberty, so as to determine optimal management. This review summarizes the available laboratory testing for the diagnosis of puberty, discussing the different assays used while reviewing the limitations of such testing.

Comparative Analysis of Commercial Immunoassays for the Determination of Total, Intact, and Nonintact Luteinizing Hormone in Urine

BACKGROUND

In our recent publications, we reported the identification of three different molecular forms of total luteinizing hormone (LH) in urine, the intact LH, the free beta-subunit (LHβ), and its core fragment of LHβ (LHβcf), the latter two establishing the nonintact portion of LH. Following the discontinuation of the Delfia immunofluorometric assay (IFMA) (Wallac, PerkinElmer Finland, Finland), a leading method for detecting urinary LH for 30 years, this study seeks to assess the efficacy of three alternative commercial immunoassays in identifying various forms of U-LH.

METHODS

Diluted urine samples underwent gel filtration to separate them into fractions, each containing different forms of LH. These were then assayed using Delfia IFMA, Architect LH (Abbott, USA), Elecsys LH Cobas (Roche, Switzerland), and Immulite 2000 LH (Siemens, Germany) immunoassays.

RESULTS

Both Delfia and Immulite assays detected total U-LH, that is, all three forms of U-LH, including intact LH, LHβ, and LHβcf. Cobas detected only intact LH and LHβ, whereas Architect detected solely the intact LH.

CONCLUSIONS

Immulite assay can be an alternative tool to detect all forms of urinary LH, a feature likely to be instrumental in developing noninvasive, practical, and scalable solutions for evaluating total U-LH changes during minipuberty in neonates, during the onset of central puberty in peripubertal children, puberty-associated disorders in adolescents, and the fertility window in women, with a special focus on postpeak changes.

Urinary gonadotropin assay on 24-h collections as a tool to detect early central puberty onset in girls: determination of predictive thresholds

STUDY QUESTION

Is the 24-h urinary gonadotropin assay an effective diagnostic tool in central precocious puberty (CPP) in girls?

SUMMARY ANSWER

This study is the first to provide 24-h urinary gonadotropin assay data, using an electrochemiluminescent immunoassay (CMIA), and to report its usefulness as a tool for the diagnosis of CPP.

WHAT IS KNOWN ALREADY

Data about the GnRH test in the diagnosis of CPP are variable and there is no consensus regarding its interpretation. The measurement of FSH and LH in urines was previously reported to be an alternative biological tool.

STUDY DESIGN, SIZE, DURATION

This is a retrospective two-cohort study, involving a setting and a validation cohort. A total of 516 girls, included between October 2012 and July 2015, and 632 urinary collections were analyzed in the setting cohort. In the validation cohort, 39 girls were included between January 2021 and May 2023, and 49 urinary collections were analyzed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

This study included girls who consulted for an investigation of disturbed growth rate or a clinical suspicion of puberty onset in different medical centres across France (setting cohort). Girls with a suspicion of precocious puberty onset were addressed at the expert centre of paediatric endocrinology of the Groupement Hospitalier Lyon Est (validation cohort). Pelvic ultrasonography was performed and enabled their classification according to clinical and morphologic changes criteria (prepubertal or pubertal groups). The parents collected 24-h urine samples (u24) according to standardized instructions. FSH and LH (urinary or plasmatic) were measured using a current and automated CMIA.

MAIN RESULTS AND THE ROLE OF CHANCE

The area under the ROC curves for CPP prediction was 0.709 for u24FSH (P < 0.001), 0.767 for u24LH (P < 0.001), and 0.753 for the u24LH/u24FSH ratio (P < 0.001). We retained all possible combinations of the four thresholds in the validation cohort (u24FSH = 1.1 or 2.0 IU/24 h; u24LH = 0.035 or 0.08 IU/24 h). The combination of u24FSH > 1.1 IU/24 h and u24LH > 0.08 IU/24 h had a positive PV of 85.7% and a negative PV of 94.3%, a sensitivity of 85.7% and a specificity of 94.3%, for classifying prepubertal and pubertal girls in this cohort.

LIMITATIONS, REASONS FOR CAUTION

This is a retrospective study, in which a margin of error remains due to the inherent uncertainty regarding the clinical assessment of pubertal onset. It must be considered that the thresholds can only apply to the used reagents; measurements without extractions using other reagents are likely to show important heterogeneity.

WIDER IMPLICATIONS OF THE FINDINGS

The assay performed herein is a simple, non-invasive, and analytically robust technique meeting the criteria for an alternative to the GnRH test which could be used to supplement its lack of sensitivity.

STUDY FUNDING/COMPETING INTEREST(S)

No specific funding was used. All authors declared no conflict of interest.

TRIAL REGISTRATION NUMBER

In-house #23-5214 registered study.

Urine Sampling Protocol Recommendations for Reliable Determination of Total Urinary Luteinizing Hormone Immunoreactivity in the Pediatric Population

This study investigates day-to-day variations in urinary luteinizing hormone (U-LH) concentrations in children, focusing on potential minimization or correction methods. 95 children and adolescents (51 boys, 44 girls, ages 5-17) provided daytime and evening urine samples for U-LH determinations over three consecutive days. No consistent day-to-day differences in U-LH levels were observed, although random variations, particularly in adolescents aged 13 or older, were noted. The net inter-assay CV% for U-LH changes over three days showed high variability, averaging 24.6% to 28.0% for boys and 21.6% to 27.3% for girls, independent of sex, collection time, or U-LH level. To reliably determine total urinary luteinizing hormone immunoreactivity in the pediatric population, it is advisable to collect multiple first-morning voided samples for at least three consecutive days as an interim solution, pending the development of a standardized protocol or correction method for varying urine composition. Strict adherence, especially for adolescents aged 13 or older, is vital.

Urinary gonadotropin measurements by enhanced luminometric assays (LIA) for the evaluation of pubertal development

OBJECTIVES

Determination of LH in urine has proved to be a reliable method for evaluation of pubertal development. The human LH assay based on time-resolved immunofluorometric (IFMA) technology (AutoDELFIA, PerkinElmer, Wallac) has been found to be suitable for this purpose thanks to its high sensitivity but other assays have not been evaluated. We have analyzed our data obtained by another potentially sensitive detection technique, enhanced luminometric assay (LIA) with the objective of finding a viable alternative to IFMA since these may not be available in the future.

METHODS

LIA was used to measure LH and FSH in serum and urine samples from 100 healthy subjects of each Tanner stage and both genders, whose pubertal development has been determined.

RESULTS

Urinary gonodotropin concentrations measured by LIA correlated well with Tanner stage [(r=0.93 for girls, r=0.81 for boys; p<0.01 for LH) and (r=0.81 for girls, r=0.73 for boys; p<0.01 for FSH)]. LIA determinations revealed the increase in U-LH concentrations during the transition from Tanner stage 1-2 in both girls and boys (p<0.001), whereas U-FSH and S-LH were able to detect the increase from Tanner stage 1-2 only in boys or girls, respectively (both p<0.001).

CONCLUSIONS

Measurement of urinary gonadotropin concentrations by LIA may be useful for the evaluation of overall pubertal development and also in the detection of transition from prepuberty to puberty.

Random urinary gonadotropins as a useful initial test for girls with central precocious puberty

Recent evidence indicates that urinary gonadotropins may be an alternative method for detecting pubertal disorders. The aim of this study was to evaluate the associations of first morning voided (FMV) and random urinary gonadotropins with the pubertal response to a gonadotropin-releasing hormone (GnRH) stimulation test to determine whether random urinary gonadotropins can be used as an alternative method for evaluating central precocious puberty (CPP). In total, 100 girls aged 6.0-8.9 years were enrolled. The subjects were divided into two groups according to their pubertal response to the GnRH stimulation test: a positive group (n = 68) and a negative group (n = 32). Random urinary luteinizing hormone (LH), follicle-stimulating hormone (FSH), and the LH:FSH ratio were significantly positively correlated with FMV urinary LH (r = 0.411, p < 0.001), FMV urinary FSH (r = 0.494, p < 0.001), and the FMV urinary LH:FSH ratio (r = 0.519, p < 0.001). The optimal cutoff values from receiver operating characteristic (ROC) curve analyses were determined to be 0.20 IU/L for random urinary LH (area under the curve (AUC) of 0.812, p < 0.001), 3.03 IU/L for random urinary FSH (AUC of 0.670, p = 0.004) and 0.08 for the random urinary LH:FSH ratio (AUC of 0.784, p < 0.001). No differences were observed between FMV and random urinary LH (p = 0.827), between FMV and random urinary FSH (p = 0.650), or between the FMV and random urinary LH:FSH ratio (p = 0.688) in ROC curve analyses with DeLong's test. Based on our findings, random urinary gonadotropins may be applicable in clinical practice as a useful initial test for girls with CPP.

Nocturnal Urinary Excretion of FSH and LH in Children and Adolescents With Normal and Early Puberty

CONTEXT

Clinical use of single serum gonadotropin measurements in children is limited by the pulsatile secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). However, first morning voided (FMV) urine may integrate the fluctuating gonadotropin serum levels.

OBJECTIVE

We aimed to evaluate urinary and serum gonadotropin levels according to age, sex, and pubertal stage in healthy children and to assess the clinical use of FMV urinary gonadotropins in children with disordered puberty.

DESIGN

Cross-sectional part of the COPENHAGEN Puberty Study and longitudinal study of patients.

SETTING

Population-based and outpatient clinic.

PATIENTS OR OTHER PARTICIPANTS

Eight hundred forty-three healthy children from the COPENHAGEN Puberty Study and 25 girls evaluated for central precocious puberty (CPP).

MAIN OUTCOME MEASURES

Clinical pubertal staging, including serum and urinary gonadotropin levels.

RESULTS

Urinary gonadotropins increased with advancing age and pubertal development and were detectable in FMV urine before physical signs of puberty. FMV urinary LH correlated strongly with basal (r = 0.871, P < 0.001) and gonadotropin-releasing hormone (GnRH)-stimulated serum LH (r = 0.82, P < 0.001). Urinary LH was superior to urinary FSH in differentiating the pubertal stage. Receiver operating curve analysis revealed that a cut-off standard deviation (SD) score of 2 for urinary LH (IU/L) gave a sensitivity of 75% and a specificity of 92% in predicting a positive GnRH stimulation test (LHmax > 5 IU/L). Urinary concentrations of LH decreased after 3 months of GnRH treatment to levels below +2 SDs.

CONCLUSIONS

Urinary gonadotropin levels increased before the onset of puberty and were elevated in girls with CPP. We suggest urinary LH as an alternative noninvasive method to improve diagnosing and therapeutic management of children with disordered puberty.

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

AIMS

We studied whether first morning voided (FMV) urinary gonadotropin measurements could be used as a noninvasive alternative to the GnRH test in the assessment of the hypothalamic-pituitary-gonadal function in children.

METHODS

In a single-center study, we compared FMV urinary gonadotropin concentrations with basal and GnRH-stimulated serum gonadotropin levels in 274 children and adolescents (78 girls, 196 boys) aged 5-17 years referred for growth and pubertal disorders. The concordance between FMV urinary gonadotropin concentrations and GnRH test results was assessed.

RESULTS

FMV urinary LH (U-LH), urinary FSH (U-FSH) and their ratios correlated well with the corresponding basal and GnRH-stimulated serum parameters (r ≥ 0.66, p < 0.001). Receiver operating characteristic curve analyses using urinary and serum LH and FSH concentrations showed that FMV U-LH and U-LH/U-FSH performed equally well as the GnRH test in the differentiation of early puberty (Tanner stage 2) from prepuberty (Tanner stage 1) (area under the curve 0.768-0.890 vs. 0.712-0.858). FMV U-LH and U-LH/U-FSH performed equally well as basal serum LH in predicting a pubertal GnRH test result (area under the curve 0.90-0.93).

CONCLUSION

FMV U-LH determination can be used for the evaluation of pubertal development and its disorders, reducing the need for invasive GnRH stimulation tests.

Follicle-stimulating hormone measured in unextracted urine: a reliable tool for easy assessment of ovarian capacity

OBJECTIVE

To determine the presence of FSH in unextracted urine of perimenopausal women using a microparticle enzyme immunoassay kit on an AxSYM random access immunoassay analyzer.

DESIGN

Controlled descriptive study.

SETTING

A large teaching hospital and infertility clinic.

PATIENT(S)

Forty perimenopausal women aged 32-55 years admitted to our clinic for a gynecological operation.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Mean serum FSH level and urinary FSH in early-morning urine, in a random void urine sample, and in 24-hour urine on the same day. FSH in urine on the day of excretion and 1 and 4 weeks thereafter, stored under various conditions. FSH in urine before and after extraction.

RESULT(S)

The Pearson's correlation coefficient between mean serum FSH levels and urinary FSH in early morning urine was 0.904, in a random void 0.915, and in 24-hour urine 0.857. Determination of optimal storage conditions revealed that urine was best kept at 4 degrees C without any additive. The correlation between FSH in extracted and unextracted urine was 98.9%.

CONCLUSION(S)

In perimenopausal women, FSH can be reliably measured in unextracted urine. The correlation between urinary FSH and a random void urine sample and mean FSH from a serial serum sample is very high. Urine can be stored for 4 weeks at 4 degrees C without loss of FSH immunoreactivity.

Monthly urinary gonadotropin and ovarian hormone excretory patterns in normal girls and female patients with idiopathic precocious puberty

To identify the developmental changes in monthly urinary gonadotropin and ovarian hormone excretion, consecutive 30-d first morning void urinary specimens were collected from 36 normal girls, one normal woman, and 15 female patients with idiopathic precocious puberty. Of these children, three normal girls and three patients with precocious puberty volunteered to collect these specimens on 2-3 occasions over a time interval of 0.5-3.2 y. When sampled, six were early prepubertal, nine late prepubertal, eight early pubertal, eight mid-pubertal, and eight late pubertal normal girls, and six were early pubertal and 14 mid-pubertal patients with precocious puberty. The mean level of monthly urinary LH, FSH, and total estrogen excretions increased with pubertal maturation. In prepuberty, the mean LH level was lower than the mean FSH level, and neither showed significant episodic fluctuations. In early puberty, mean FSH levels increased with remarkable fluctuations, and mean LH levels were low with few variations in the course of a month. At the onset of puberty, gonadotropin excretory patterns underwent specific changes, showing at the same time periodically and every other day fluctuating patterns. Urinary total estrogen and pregnanediol excretion fluctuated independently from these periodic variations in urinary gonadotropins. These patterns were observed in six out of 16 patterns in normal pubertal girls and 10 out of 20 patterns in precocious puberty. Once the urine LH level exceeded the urine FSH level, however, these periodic variations disappeared. The cycle of a normal postmenarcheal girl aged 14 y showed a pattern similar to that of a normal adult. In patients with precocious puberty, the hormonal patterns were similar to those of sexual stage-matched normal girls.

Stability of urinary female reproductive hormones stored under various conditions

Urinary reproductive hormones afford specific and sensitive evaluation of female reproductive potential in epidemiologic and clinical settings. The goal of this study was to characterize the stability of urinary luteinizing hormone, follicle stimulating hormone, estrone 3-glucuronide, pregnanediol 3-glucuronide, and creatinine during storage as functions of time, temperature, and additives. After 2 weeks with no additives, activity of the four analytes, relative to initial concentrations, ranged from 91.9 to 102.8% at 4 degrees C, 35.1 to 89.6% at 25 degrees C, and 7.5 to 66.9% at 37 degrees C. Antimicrobial additives did not consistently improve stability. Analyte activity for samples stored with no additives for 24 weeks at -80 degrees C ranged from 69.0 to 101.2%. Glycerol and bovine serum albumin improved analyte stability; activity ranged from 91.1 to 106.3%. Other additives were ineffective. These results reveal conditions for storing reproductive hormone analytes in urine during epidemiologic field studies.