Hypogonadism with Normal Serum Testosterone

Testosterone, measured by a 1-step chemiluminescent immunoassay (Abbott Architect, second generation testosterone assay) was 16.0 nmol/L (reference interval 4.9-32 nmol/L); his sex hormone-binding globulin (SHBG)3 was increased at 153 nmol/L (13.5-71.4 nmol/L) as were luteinizing hormone (LH) and folliclestimulating hormone (FSH) at 33.4 IU/L (0.6-12.0 IU/L) and 54.7 IU/L (1.0-11.9 IU/L), respectively (Table 1). Serum testosterone measurement is rec ommended if features of hypogonadism are present, including reduced libido, erectile dysfunction, small testicles, gynecomastia, hot flushes, loss of body hair, infertility, reduced bone density, and loss of muscle strength, and should also be considered in those individuals with reduced energy, low mood, sleep disturbance, mild anemia, and diminished physical performance (1). DOI: 10.1373/clinchem.2016.265124 © 2016 American Association for Clinical Chemistry POINTS TO REMEMBER * Diagnosis of male LOH requires clinical features of androgen deficiency, consistently low testosterone concentration, and exclusion of classical causes of hypogonadism. * Interpretation of serum total testosterone is affected by many factors, including circadian rhythm, acute illness, age, adiposity, variations in analytical techniques, and SHBG concentration. Fax +353-014143931; e-mail: ingridborovickova@hotmail.com. 3 Nonstandard abbreviations: SHBG,sex hormone-binding globulin; LH, luteinizing hormone; FSH, follicle-stimulating hormone; bioT, bioavailable testosterone; FT, free testosterone; LOH, late-onset hypogonadism.