Diagnostic Approach and Management of Hypogonadism

Diagnostic Confirmation

The American College of Physicians recommends obtaining a second fasting morning testosterone measurement to confirm the diagnosis, as testosterone exhibits significant diurnal variation and single measurements are insufficient for diagnosis 1
The current total testosterone of 352 ng/dL is technically above the 300 ng/dL threshold used by the American Urological Association to define hypogonadism, but the free testosterone of 5.9 ng/dL requires proper interpretation with validated reference ranges 1, 2

Measure sex hormone-binding globulin (SHBG) to understand the relationship between total and free testosterone, particularly important in men with obesity where low SHBG can artificially lower total testosterone while free testosterone may be normal 2, 3
If testosterone levels are confirmed low on repeat testing, measure luteinizing hormone (LH) and follicle-stimulating hormone (FSH) to distinguish primary (testicular) from secondary (pituitary-hypothalamic) hypogonadism 2

Initiate testosterone therapy only if morning free testosterone by equilibrium dialysis is frankly low on at least 2 separate assessments, and the patient has symptomatic androgen deficiency 2, 4

Target mid-normal testosterone levels (500-600 ng/dL) during treatment 4
Transdermal preparations (gels, patches) applied daily may have variable absorption, while intramuscular testosterone enanthate can provide more reliable levels 4, 5

Recheck testosterone levels 2-3 months after initiating therapy or any dose adjustment to allow steady-state levels 4
Continue assessing symptom improvement (energy, libido, muscle mass) alongside laboratory values 4