From the Guidelines
For male gynecomastia, the recommended initial lab tests include serum estradiol, as it should be measured in testosterone deficient patients who present with breast symptoms or gynecomastia prior to the commencement of testosterone therapy 1. The initial evaluation of male gynecomastia should focus on identifying potential hormonal imbalances or underlying conditions that may be causing the symptoms.
- Key lab tests to consider include:
- Estradiol: to assess the balance between male and female hormones, particularly in patients with low total testosterone and low or low/normal LH levels 1
- Total testosterone: to evaluate testosterone deficiency, which may be associated with gynecomastia
- Luteinizing hormone (LH) and follicle-stimulating hormone (FSH): to provide information about pituitary function and potential hypogonadism
- Prolactin: to screen for hyperprolactinemia, which may be caused by pituitary tumors such as prolactinomas 1 Additional tests may be ordered based on initial results or clinical suspicion, such as thyroid-stimulating hormone (TSH) to screen for thyroid disorders, liver function tests (AST, ALT) to detect liver disease, and human chorionic gonadotropin (hCG) to rule out testicular tumors. It is essential to note that if all lab results are normal, the gynecomastia may be idiopathic or due to medications or lifestyle factors, and addressing these factors or considering surgical intervention may be necessary. The most critical aspect of managing male gynecomastia is to identify and address any underlying hormonal imbalances or conditions that may be contributing to the symptoms, and serum estradiol measurement is a crucial part of this evaluation 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Laboratory Investigations for Male Gynecomastia
The following laboratory investigations are indicated for male gynecomastia:
- Testosterone (T) 2, 3, 4, 5, 6
- Estradiol (E2) 2, 3, 4, 5, 6
- Sex hormone-binding globulin (SHBG) 2, 3, 4
- Luteinizing hormone (LH) 2, 3, 4, 5, 6
- Follicular stimulating hormone (FSH) 2, 3, 4
- Thyroid stimulating hormone (TSH) 2, 3, 4, 5
- Prolactin 2, 3, 4, 5
- Human chorionic gonadotropin (hCG) 2, 3
- Alpha-fetal protein (AFP) 2
- Liver and renal function tests 2, 4, 5
Rationale for Laboratory Investigations
These laboratory investigations are aimed at establishing an underlying cause of gynecomastia, such as hormonal imbalances or testicular dysfunction 3, 4, 5. The results of these investigations can help guide further management and treatment of gynecomastia 2, 5.
Additional Evaluations
Additional evaluations, such as breast imaging and testicular ultrasound, may also be necessary to rule out other conditions, such as breast cancer or testicular tumors 2, 4.