Should a male patient with hypogonadism and normal total testosterone levels (402 ng/dL), suppressed Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) levels, and normal thyroid function continue testosterone therapy?

Assessment of Current Testosterone Therapy Status

The laboratory findings confirm appropriate continuation of testosterone therapy, as the patient demonstrates adequate testosterone levels (402 ng/dL) with expected suppression of the hypothalamic-pituitary-gonadal axis (LH and FSH <0.3 mIU/mL), which is the physiological response to exogenous testosterone replacement. 1

Understanding the Laboratory Pattern

The current hormonal profile is entirely consistent with ongoing testosterone therapy:

• Total testosterone of 402 ng/dL is within the therapeutic target range of mid-normal levels (350-600 ng/dL), which is the recommended goal for men on testosterone replacement therapy 1, 2
• Suppressed LH and FSH (<0.3 mIU/mL) are expected and appropriate during testosterone therapy, as exogenous testosterone provides negative feedback to the hypothalamic-pituitary axis, suppressing gonadotropin secretion 3
• This suppression pattern confirms adequate testosterone absorption and bioavailability, as the body's regulatory system is responding appropriately to the exogenous hormone 3

Critical Distinction: Cannot Diagnose Type of Hypogonadism While On Therapy

A fundamental pitfall to avoid: you cannot determine whether this patient has primary versus secondary hypogonadism based on these labs because he is currently on testosterone therapy. 1

• The suppressed gonadotropins are an artifact of the testosterone therapy itself, not a reflection of the patient's underlying pathophysiology 1
• To differentiate primary from secondary hypogonadism, testosterone therapy must be discontinued with a 2-4 week washout period to allow recovery of the hypothalamic-pituitary-gonadal axis 1
• After washout, morning testosterone levels should be measured on two separate occasions, followed by LH and FSH measurement if testosterone remains low 4, 5
• Elevated LH/FSH with low testosterone indicates primary (testicular) hypogonadism, while low or inappropriately normal LH/FSH with low testosterone indicates secondary (hypothalamic-pituitary) hypogonadism 5

Hormonal Standpoint: Continuation is Appropriate

From a purely hormonal perspective, continuation is justified if:

• The patient has documented symptoms of hypogonadism (diminished libido, erectile dysfunction, reduced sense of vitality) that improved with therapy 4, 1
• The original diagnosis was confirmed with two morning testosterone measurements <300 ng/dL before therapy initiation 4, 2
• Current testosterone levels are therapeutic (402 ng/dL is appropriate) 1

Essential Monitoring Requirements

If continuing therapy, the following monitoring is mandatory 1, 2:

• Hematocrit must be checked - withhold therapy if >54% and consider phlebotomy, as erythrocytosis is a significant risk, particularly with injectable testosterone 1, 2
• PSA monitoring in men over 40 years - refer for urologic evaluation if PSA increases >1.0 ng/mL in first 6 months or >0.4 ng/mL per year thereafter 1
• Clinical symptom response assessment - testosterone therapy produces small but significant improvements in sexual function (standardized mean difference 0.35) but little to no effect on physical functioning, energy, vitality, or cognition 1
• Testosterone levels should be monitored every 6-12 months once stable levels are confirmed 1

Fertility Considerations: Absolute Contraindication

If this patient desires fertility now or in the near future, testosterone therapy is absolutely contraindicated and must be discontinued immediately 1, 5:

• Exogenous testosterone suppresses spermatogenesis and causes azoospermia through suppression of LH and FSH 1, 5
• For men with secondary hypogonadism seeking fertility, gonadotropin therapy (hCG plus FSH) is mandatory, as it stimulates the testes directly while maintaining testosterone production 1, 5
• This suppression can be prolonged even after discontinuation of testosterone 1

Clinical Decision Algorithm

Continue testosterone therapy if:

1. Original diagnosis was confirmed with two morning testosterone measurements <300 ng/dL 4
2. Patient had specific symptoms (diminished libido, erectile dysfunction) that improved with therapy 4, 1
3. Patient does not desire fertility 1, 5
4. No absolute contraindications exist (hematocrit >54%, active prostate/breast cancer, recent cardiovascular event) 1, 2
5. Monitoring parameters (hematocrit, PSA) remain within acceptable ranges 1, 2

Discontinue testosterone therapy and pursue alternative evaluation if:

1. Patient desires fertility - switch to gonadotropin therapy 1, 5
2. No symptomatic improvement after 12 months of therapy 1
3. Development of contraindications (erythrocytosis, prostate concerns) 1, 2
4. Original diagnosis was never properly confirmed with two low morning testosterone measurements 4

Realistic Expectations

Patients should understand that testosterone therapy provides 1:

• Small but significant improvements in sexual function and libido (standardized mean difference 0.35)
• Modest quality of life improvements, primarily in sexual function domains
• Little to no effect on physical functioning, energy, vitality, depressive symptoms, or cognition
• Potential metabolic benefits including improvements in insulin resistance and lipid profiles