Essential Laboratory Testing for Male Patients with Suspected Testosterone Deficiency

Core Laboratory Panel

The American Urological Association recommends measuring serum luteinizing hormone (LH) in every patient with confirmed low testosterone to determine whether hypogonadism is primary (testicular) or secondary (hypothalamic-pituitary) 1, 2, 3
Low or low-normal LH with low testosterone indicates secondary hypogonadism and triggers additional pituitary evaluation, with a strength of evidence level of high 1, 2
The Endocrine Society suggests measuring prolactin only when testosterone is low and LH is low or low-normal, as elevated prolactin requires endocrinology referral for possible prolactinoma 1, 2, 3
The American College of Physicians recommends measuring baseline hemoglobin and hematocrit before initiating testosterone therapy to monitor polycythemia risk during treatment, with a strength of evidence level of moderate 1, 3
The Urological Association recommends measuring prostate-specific antigen (PSA) in all men over 40 years before starting testosterone therapy to minimize the risk of prescribing testosterone to men with occult prostate cancer 1

The American Society for Reproductive Medicine suggests measuring follicle-stimulating hormone (FSH) in men interested in fertility preservation, as elevated FSH with low testosterone indicates impaired spermatogenesis 1, 2, 3
The Endocrine Society recommends measuring estradiol only in patients presenting with breast symptoms or gynecomastia, as elevated baseline estradiol requires endocrinology referral 1, 2, 3
The American Heart Association suggests assessing lipid panel and glucose/HbA1c to evaluate cardiovascular risk factors before testosterone therapy, with a strength of evidence level of high 1, 3

The clinical algorithm for laboratory ordering involves a step-by-step approach, including confirming low testosterone, ordering mandatory baseline labs, and adding conditional labs based on presentation, with a strength of evidence level of high 1, 2, 3, 4, 6

The American Urological Association advises against skipping LH measurement, as it is the single most important test to differentiate primary from secondary hypogonadism, with a strength of evidence level of high 1, 2, 3
The Endocrine Society recommends against measuring prolactin in patients with normal or elevated LH, as this wastes resources and provides no diagnostic value, with a strength of evidence level of moderate 1, 2, 3
The American College of Physicians suggests against delaying pituitary MRI when testosterone is <150 ng/dL with low/low-normal LH, as non-secreting adenomas may be present even with normal prolactin, with a strength of evidence level of high 1, 2, 3