When do you refer a patient for low testosterone?

When to Refer a Patient for Low Testosterone

You should refer patients to endocrinology or urology when you confirm biochemical hypogonadism (two morning testosterone levels <300 ng/dL) with consistent symptoms, but particularly when secondary hypogonadism is identified (low testosterone with low/low-normal LH), when pituitary pathology is suspected, or when fertility preservation is desired. 1, 2

Initial Evaluation in Primary Care

Before considering referral, complete the diagnostic workup:

Biochemical Confirmation Required

• Obtain two separate morning (8-10 AM) total testosterone measurements using the same laboratory and methodology 1, 2, 3
• Both measurements must be <300 ng/dL to confirm testosterone deficiency 1, 2
• Never measure testosterone at random times due to diurnal variation—afternoon/evening measurements will be physiologically lower and lead to false-positive diagnoses 2

Clinical Symptoms Must Be Present

Diagnosis requires BOTH low testosterone levels AND symptoms—do not treat based on laboratory values alone 2, 4

Key symptoms warranting evaluation:

• Reduced libido or sexual dysfunction 1, 2
• Erectile dysfunction 1, 4
• Persistent fatigue and reduced energy/endurance 1, 2
• Reduced muscle mass and strength 1, 5
• Depression, reduced motivation, or poor concentration 1, 2
• Gynecomastia 1
• Male infertility 1

Physical examination findings:

• Reduced body hair in androgen-dependent areas 1, 2
• Increased BMI or waist circumference 1, 2
• Small or soft testes 1
• Gynecomastia 1

Specific Indications for Specialist Referral

Mandatory Referral Situations

Secondary hypogonadism (low testosterone with low/low-normal LH):

• Measure serum LH in all patients with confirmed low testosterone to distinguish primary from secondary hypogonadism 1, 2
• If LH is low or low-normal, measure serum prolactin to screen for hyperprolactinemia and possible pituitary tumors 1, 2
• Consider pituitary MRI if testosterone is low with low/low-normal LH 6
• These patients require endocrinology evaluation for potential pituitary pathology 1

Fertility preservation desired:

• Testosterone therapy causes azoospermia and is contraindicated in men desiring fertility 3, 7
• Refer to reproductive endocrinology or urology for gonadotropin therapy (hCG + FSH) or selective estrogen receptor modulators instead 2

Suspected pituitary pathology:

• Visual field changes (bitemporal hemianopsia) suggest pituitary tumor 1
• Anosmia suggests Kallmann syndrome 1
• Elevated prolactin warrants immediate endocrinology referral 1, 2

Consider Referral for Complex Cases

High-risk medical conditions requiring specialist input:

• Unexplained anemia (even without symptoms)—measure testosterone in all such patients 1, 2
• Bone density loss or osteoporosis 1, 2
• HIV/AIDS 1, 2
• History of chemotherapy or testicular radiation 1
• Chronic narcotic or corticosteroid use 1, 6
• Chronic liver disease with evidence of hypogonadism 1

Obesity with borderline results:

• In obese patients, measure free testosterone by equilibrium dialysis and sex hormone-binding globulin (SHBG) 2
• Low total testosterone may be due solely to low SHBG with normal free testosterone 2
• If free testosterone is also low on at least 2 assessments, consider referral for treatment after completing workup 2

When Primary Care Can Manage Without Referral

Primary hypogonadism (low testosterone with elevated LH/FSH):

• These patients have testicular failure and typically can be managed in primary care if no contraindications exist 1, 7
• Initiate testosterone replacement therapy aiming for mid-normal range (350-750 ng/dL) 2

Straightforward cases appropriate for primary care management:

• Clear primary hypogonadism with no fertility concerns 1, 7
• No contraindications to testosterone therapy (prostate cancer, breast cancer, hematocrit >50%, severe BPH with IPSS >19, class III-IV heart failure) 3, 7
• Patient does not desire fertility preservation 2, 7

Critical Monitoring Requirements If Managing in Primary Care

Baseline testing before initiating therapy:

• Hemoglobin/hematocrit (withhold if hematocrit >50%) 2
• PSA in men over 40 years 2, 3
• Cardiovascular risk assessment including lipid profile 2

During treatment monitoring:

• Hematocrit >54% requires immediate intervention (dose reduction, temporary discontinuation, or phlebotomy) 2
• Injectable testosterone carries highest erythrocytosis risk (43.8% of patients) compared to transdermal formulations 2
• Most hematocrit changes occur within first 3 months, making early monitoring critical 2

Common Pitfalls to Avoid

• Do not rely on screening questionnaires alone for diagnosis 1
• Do not diagnose based on a single testosterone measurement 1, 2
• Do not measure testosterone at random times of day 1, 2
• Do not overlook free testosterone measurement in obese patients 1, 2
• Do not start testosterone therapy without confirming both low levels AND clinical symptoms 2, 4