Diagnostics · Hormone Testing
Abstract
Objective
To investigate whether routine assessment of free testosterone improves the diagnostic accuracy of functional hypogonadism.
Methods
Total and free testosterone (calculated on SHBG levels) were determined in 188 patients with sexual symptoms and 184 with infertility.
Results
Hypogonadism (calculated free testosterone <63 pg/ml) was found in 47/188 (25.0%) patients with sexual symptoms and in 21/184 (11.4%) with infertility. Total testosterone determination misdiagnosed hypogonadism in 8.4% (12/143) of men with sexual symptoms and in 2% (3/152) with infertility. In subjects with borderline total testosterone, only 24.7% (19/77) had hypogonadism confirmed by free testosterone levels. Free testosterone levels significantly correlated with age, haematocrit, gonadotropins, gynecomastia, BMI, and number of co-morbidities, whereas total testosterone associated only with the latter two. Furthermore, age, haematocrit, BMI, and the presence of erectile dysfunction and of low libido were significantly different between men with normal and low free testosterone, whereas only BMI and low libido were significantly different between patients with normal and low total testosterone.
Conclusion
Routine assessment of free testosterone allows a more accurate diagnosis of functional hypogonadism, especially in men with sexual symptoms. Free testosterone levels associate with clinical and biochemical parameters of androgen deficiency better than total testosterone levels.
Topics
By this author
Semen Analysis · Sperm Function Testing
Preimplantation genetic testing for male factor infertility: lights and shadows
Mazzilli R et al., 2026 · Journal of endocrinological investigation
Male factor could contribute, alone or in combination with female factor, to the inability to conceive in a couple in more than half of cases. The effect of male factor infertility (MFI) on embryological assisted reproductive technology (ART) outcomes remains an ongoing discussion. to evaluate the impact of MFI on embryo aneuploidy rates, to better understand the role and possible indication for Preimplantation genetic testing for aneuploidies (PGT-A), considering the role of sperm characteristics, paternal age, sperm DNA fragmentation and sperm aneuploidies. this narrative review included all available articles, published up to January 2026. Available evidence, often based on heterogeneous and old-fashioned methodologies, suggests that MFI may impair embryonic development, particularly in terms of fertilization rate and blastulation rate, more than embryo euploidy; however, a comprehensive evaluation of MFI should be integrated into clinical practice in the context of couple infertility, to also optimize the efficiency and outcomes of ART. Promising results emerged from sperm DNA fragmentation as a tool to predict embryo euploidy, but further investigations involving larger sample sizes and improved standardization are required.
Neoplastic Risk in Patients With Klinefelter Syndrome
Graziani A et al., 2026 · Andrology · Free to read
Besides gonadal involvement (hypogonadism, male factor infertility, and testicular hypotrophy), patients with Klinefelter syndrome (KS) may suffer from several extra-gonadic complications, including neoplastic events. The aim of this review is to summarize all major clinical evidence dealing with the association between KS and neoplastic diseases and provide practical suggestions for the management of patients with KS regarding neoplastic risk. This narrative review was conducted through a comprehensive search of the PubMed database, using combinations of the following keywords: "Klinefelter syndrome," "cancer," "neoplasm," "breast cancer," "germ cell tumor," "lymphoma," and "testosterone replacement therapy". KS is associated with a higher risk of breast cancer and mediastinal germ cell tumors and an apparent higher risk of hematological malignancies, in particular non-Hodgkin lymphoma and leukemia. Evidence on testicular cancer is limited, with no clear increase in risk attributable to KS, while prostate cancer has a lower risk and lower mortality rate. Given the complexity of the syndrome and the limited available evidence, regular clinical follow-up with targeted investigations when clinically indicated may facilitate early diagnosis and management of associated comorbidities.
Evidence Synthesis · Systematic Reviews
Body composition in male hypogonadism: practical considerations to the use of dual-energy x-ray absorptiometry
Delbarba A et al., 2026 · Reviews in endocrine & metabolic disorders · Free full text on PubMed Central
Male hypogonadism is associated with significant alterations in body composition, including reduced lean body mass (LBM), increased fat body mass (FBM), particularly visceral adiposity, and impaired muscle function, contributing to frailty and cardiometabolic risk. These changes reflect the disruption of a complex endocrine crosstalk among bone, muscle, and adipose tissue, mediated by cytokines such as osteokines, myokines, and adipokines. This dysregulation promotes the development of osteosarcopenic obesity, a condition characterized by the coexistence of low bone mass, sarcopenia, and excess adiposity. Testosterone (T) plays a central role in maintaining body composition by stimulating muscle protein synthesis, inhibiting adipogenesis, and preserving bone health. Its deficiency, irrespective of etiology, leads to rapid impairment of anabolic pathways, resulting in decreased lean mass and increased fat accumulation. Evidence from clinical and experimental models demonstrates that these alterations are partially reversible with T replacement therapy (TRT), although variability exists depending on the underlying cause of hypogonadism. Dual-energy X-ray absorptiometry (DXA) represents the gold standard for assessing bone mineral density (BMD) and a key tool for evaluating body composition through a three-compartment model. It allows precise quantification of fat and lean mass, as well as their regional distribution, with minimal radiation exposure. In this review, we provide a comprehensive and clinically oriented overview of body composition alterations in male hypogonadism, focusing on underlying pathophysiological mechanisms and the practical application of DXA across different clinical scenarios. We discuss evidence from conditions such as Klinefelter syndrome, Kallmann syndrome, androgen deprivation therapy, HIV infection, and transgender care, aiming to offer a pragmatic framework for integrating body composition assessment into routine practice and improving patient management.
Bone Mineral Density · Measurement
Impact of reference gender on bone mineral density and fracture risk assessment in transgender adults
Scala A et al., 2026 · Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA · Free full text on PubMed Central
In transgender adults, reference-gender choice alters Z-scores and fracture-risk estimates. Z-scores differ by 0.4-0.6 SD, with male references identifying more individuals with low BMD for age, especially in those assigned male at birth. Dual-reference reporting is advisable until further evidence becomes available. Transgender individuals, especially those assigned male at birth (AMAB), exhibit lower bone mineral density (BMD) compared with the cisgender population. Interpretation of densitometric data is challenging, as the choice of reference gender can significantly influence Z-scores and fracture risk scores. This study aims to evaluate the impact of the gender reference database (male or female) on the assessment of BMD and fracture risk in transgender adults prior to gender-affirming hormone therapy (GAHT). We conducted a cross-sectional analysis of 249 transgender individuals (153 assigned female at birth - AFAB and 96 AMAB) aged 18-43 years, recruited in the Hospitals of Padua and Brescia (Italy). Z-scores were calculated using both male and female reference databases and FRAX scores were computed using both gender inputs. Associations with anthropometric, biochemical, and hormonal parameters were explored. Z-scores differed systematically depending on the reference gender, with mean ΔZ ranging 0.4-0.6 SD across skeletal sites. Switching reference databases frequently led to reclassification of BMD status. AMAB individuals showed a higher prevalence of low BMD for age, particularly when assessed against male references (27.1%), whereas AFAB participants generally maintained normal BMD. However, FRAX scores remained low. BMI and 25-OH vitamin D levels were independent predictors of BMD and Z-scores in AMAB individuals. The choice of reference gender significantly influences densitometric interpretation in young transgender adults. Until further evidence becomes available, calculating Z-scores using both male and female reference databases is advisable. Early preventive interventions remain essential to preserve bone health.
Related research
Hormone Testing · Serum Panels
The importance of SHBG and calculated free testosterone for the diagnosis of symptomatic hypogonadism in HIV-infected men: a single-centre real-life experience
Pezzaioli LC et al., 2021 · Infection · Free full text on PubMed Central
The prevalence of low testosterone and symptoms of hypogonadism in HIV-infected men is still debated. We aimed to estimate the prevalence and type of hypogonadism in HIV-infected males complaining about sexual symptoms, and to evaluate the role of calculated free testosterone (cFT) vs total testosterone (TT) for diagnosis. Furthermore, we evaluated relationship between sex hormone-binding globulin (SHBG), gonadal status and clinical and virologic parameters. We retrospectively evaluated 169 HIV-infected men with sexual symptoms, with TT available. Among them, we selected 94 patients with TT, SHBG, cFT, and luteinizing hormone (LH) available, and classified hypogonadism into overt (low TT and/or low cFT) and compensated (high LH, normal TT and cFT). Comparison was performed by non-parametric Kruskal-Wallis test and Spearman's correlation was calculated to verify the possible associations. Overt and compensated hypogonadism were found in 20.2% and 13.8% of patients, respectively. With reliance on TT alone, only 10.6% of patients would have met diagnosis. SHBG values were elevated in one third of patients, and higher in men with compensated hypogonadism. Significant positive correlation was found between SHBG and HIV infection duration, TT and LH. Only a complete hormonal profile can properly diagnose and classify hypogonadism in HIV-infected men complaining about sexual symptoms. TT alone reliance may lead to half of diagnoses missing, while lack of gonadotropin prevents the identification of compensated hypogonadism. This largely comes from high SHBG, which seems to play a central role in the pathogenesis of hypogonadism in this population.
Association of bioavailable, free, and total testosterone with insulin resistance: influence of sex hormone-binding globulin and body fat
Tsai EC et al., 2004 · Diabetes Care
Previous reports of an association between low testosterone levels and diabetes risk were often confounded by covariation of sex hormone-binding globulin (SHBG) and testosterone measurements. Measurements of bioavailable and free testosterone, more reliable indexes of biologically active testosterone, were examined for their associations with markers of insulin resistance and body fat measures in 221 middle-aged nondiabetic men. Bioavailable and free testosterone were calculated from the concentrations of total testosterone, SHBG, and albumin, and they were not significantly correlated with SHBG (r = 0.07-0.1). In contrast, total testosterone correlated significantly with SHBG (r = 0.63). We evaluated the relationship between these measures of circulating testosterone and markers for insulin resistance (i.e., fasting insulin, C-peptide, and homeostasis model assessment for insulin resistance [HOMA-IR]) as well as total body fat (assessed by dual-energy X-ray absorptiometry [DEXA]) and abdominal fat distribution (assessed by single-slice computed tomography [CT]). Bioavailable, free, and total testosterone and SHBG all correlated significantly with fasting insulin (age-adjusted r = -0.15 [P = 0.03], -0.14 [P = 0.03], -0.32 [P < 0.0001], and -0.38 [P < 0.0001], respectively), fasting C-peptide (r = -0.18 [P = 0.009] to -0.41 [P < 0.0001]), HOMA-IR (r = -0.15 [P = 0.03] to - 0.39 [P < 0.0001]), and body fat measures (r = -0.17 [P = 0.008] to -0.44 [P < 0.0001]). Only SHBG and total testosterone were significantly associated with fasting glucose (r = -0.20 [P = 0.003] to -0.21 [P = 0.002]). In multivariate analysis, bioavailable or free testosterone was significantly and inversely associated with insulin, C-peptide, and HOMA-IR, but this was not independent of total body or abdominal fat. SHBG was a significant determinant of insulin, C-peptide, and HOMA-IR, independent of body fat. The associations between total testosterone and insulin resistance were confounded by SHBG. The inverse association between testosterone and insulin resistance, independent of SHBG, was mediated through body fat.
Male Endocrine and Genetic Factors · Male Hormonal Axis
Sperm Count and Hypogonadism as Markers of General Male Health
Ferlin A et al., 2021 · European urology focus
Some evidence suggests that infertile men, who are at increased risk for hypogonadism, metabolic derangements, and osteoporosis, have higher long-term morbidity and mortality than controls, but data are scarce and not conclusive. We tested whether semen quality and reproductive function could represent a marker of general male health. DESIGN, SETTING, A retrospective study of 5177 individuals from a prospectively collected database of 11516 males of infertile couples who had semen analysis in a tertiary university center. OUTCOME MEASUREMENTS Of them, 5177 had all data for reproductive hormones, testis ultrasound, and biochemical determinations for glucose and lipid metabolism. Hypogonadism was defined as testosterone <10.5nmol/l and/or luteinizing hormone >9.4 IU/l. Individuals with a total sperm count of <10 million had genetic testing (karyotype, Y chromosome microdeletions, and CFTR gene mutations) and those with hypogonadism underwent dual-energy x-ray absorptiometry for bone mineral density. Descriptive statistics and odds ratio (OR) calculation were used. Men with a low sperm count (<39 million/ejaculate) are at a high risk of hypogonadism (OR 12.2, 95% confidence interval [CI] 10.2-14.6) and have higher body mass index, waist circumference, systolic pressure, low-density lipoprotein cholesterol, triglycerides, and homeostatic model assessment (HOMA) index; lower high-density lipoprotein cholesterol; and a higher prevalence of metabolic syndrome (OR 1.246, 95 CI 1.005-1.545). All data are worse in men with hypogonadism, but a low sperm count per se is associated with a poor metabolic parameter. Men with hypogonadism have lower bone mineral density and 51% prevalence of osteoporosis/osteopenia. Longitudinal studies are necessary to support these data. This is the largest study with comprehensive evaluation of semen quality and reproductive function, etiology and risk factor determination, and metabolic, cardiovascular, and osteoporosis risk assessment, performed in men referred for fertility evaluation. A low sperm count is associated with poorer metabolic, cardiovascular, and bone health. Hypogonadism is mainly involved in this association, but a low sperm count in itself is a marker of general health. This large study evaluated semen quality, reproductive function, and metabolic risk in men referred for fertility evaluation, and showed that a man's semen count is a marker of his general health. Men with low sperm counts are more likely than those with normal sperm counts to have greater body fat, higher blood pressure, higher "bad" (low-density lipoprotein) cholesterol and triglycerides, and lower "good" (high-density lipoprotein) cholesterol. They also have a higher frequency of metabolic syndrome and insulin resistance, a condition that can lead to diabetes. Men with low sperm counts had a 12-fold increased risk of hypogonadism or low testosterone levels, and half of them had osteoporosis or low bone mass. Fertility evaluation gives men the unique opportunity for health assessment and disease prevention.
Hormonal Agents · Androgens and DHEA
Plasma metabolomics in male primary and functional hypogonadism
Grande G et al., 2023 · Frontiers in endocrinology · Free full text on PubMed Central
Metabolomics proposes to unveil the molecular machinery involved in each specific disease by the comprehensive analysis of low-molecular-weight metabolites in a biological sample. This narrative mini-review analyzes previous studies applying ultra-high-performance liquid chromatography-high-resolution mass spectrometry (HRMS)-based metabolomics to highlight different metabolic pathways involved in male hypogonadism and testosterone replacement therapy, both in the case of insulin-sensitive patients with primary hypogonadism and in the case of insulin-resistant patients with functional hypogonadism. In functional hypogonadism, metabolomics revealed that different biochemical pathways are affected. In detail, glycolysis is the most important biochemical process involved in these patients. Glucose metabolism is fueled by amino acid degradation, and gluconeogenesis is widely stimulated. Some important pathways, including glycerol, are compromised. Furthermore, mitochondrial electron transport is influenced, namely, by a decrease in ATP production. On the contrary, beta-oxidation of short- and medium-chain fatty acids does not represent an energy source in hypogonadal patients. Both lactate and acetyl-CoA are converted into ketone bodies, which increased immensely. However, carnosine and β-alanine are greatly reduced. These metabolic changes are associated with increased fatigue and mental confusion. After testosterone replacement therapy, a complete restoration is achieved for only a part of the metabolites. It is of note that only in patients with functional hypogonadism treated with testosterone are ketone bodies produced at high levels, so the symptoms sometimes reported by these patients after the beginning of the therapy (difficulty in concentrating, depressed mood, brain fog, and memory impairment) might represent a specific "keto flu-like" syndrome, related to the metabolic ketonic state.
Diagnostics › Hormone Testing › Serum Panels · Research Methods › Measurement and Statistics › Outcome Definitions
Paolo Facondo, Elena Di Lodovico, Letizia Chiara Pezzaioli, Carlo Cappelli, Andrea Delbarba
P Facondo, E Lodovico, L Pezzaioli, C Cappelli, A Delbarba
PMID 35243960 35243960 DOI 10.1080/13685538.2022.2046727 10.1080/13685538.2022.2046727 Facondo et al. 2022, Facondo 2022