Tests
1st tests to order
serum total testosterone
Test
Testosterone should be measured in all men with otherwise unexplained erectile dysfunction, anemia, osteoporosis, gynecomastia, vasomotor flashing/sweating, myopathy, or absence/loss of secondary sexual characteristics.[1][2]
Check fasting levels between 6 a.m. and 8 a.m. ideally; sample taken up to 11 a.m. is acceptable.
Result
below 300 nanograms/dL generally is accepted as being consistent with hypogonadism
Tests to consider
serum sex hormone binding globulin (SHBG)
Test
Should be checked in men with an equivocal or borderline total testosterone, and can be used to calculate the serum free testosterone, which is generally more accurate than values run on serum samples.[35][36]
Altered SHBG levels are suspected in older men and in men with underlying conditions, such as obesity, diabetes mellitus, nephrotic syndrome, or liver or thyroid disease.[34]
Result
increased or decreased
calculated free testosterone
Test
In men who have conditions that alter sex hormone binding globulin (SHBG), or when total testosterone is in the borderline range for patients with clinical features suggestive of androgen deficiency, a calculated free testosterone estimate is used to confirm testosterone deficiency.[7]
Calculated free testosterone levels can be performed using validated equations based on the total testosterone, SHBG, and, in some equations, the albumin level. The Vermeulen equation for free testosterone is the most commonly used.[2]
Each laboratory has its own combination of assays and specific reference ranges and decision limits for free testosterone, such that close collaboration between clinical and laboratory specialists is required.[2]
Result
less than 58 picograms/mL consistent with hypogonadism
serum LH/FSH
Test
Serum luteinizing hormone (LH) and follicle stimulating hormone (FSH) are measured if on testosterone levels are found to be consistently low to determine whether the patient has primary or secondary hypogonadism.
Result
in patients with low testosterone, elevated serum LH/FSH levels indicate primary hypogonadism; decreased or normal serum LH/FSH levels indicate secondary (also known as central or hypogonadotropic) hypogonadism
semen analysis
Test
Performed in men who have low testosterone levels and report infertility, or who express a desire to start a family in the future.
Determines concentration, motility, and morphological appearance of spermatozoa.
Two semen analyses (each with samples obtained after 2 to 7 days of abstinence) are recommended to make an accurate diagnosis.
If a semen volume of less than 1 mL is seen on analysis, ask the patient if the entire sample was collected in the cup.
Result
sperm count concentration less than 5 million/mL indicates severe oligozoospermia (sperm count less than 16 million/mL is considered oligospermic); sperm motility less than 40% indicates asthenospermia; less than 4% morphologically normal sperm indicates teratospermia
CBC
Test
Normochromic normocytic anemia is a typical feature in all forms of male hypogonadism.[7]
Prior to initiation of testosterone therapy, all patients should undergo baseline assessment of hemoglobin/hematocrit.[1]
Result
low or low-normal hemoglobin or hematocrit consistent with hypogonadism; high or high-normal levels make hypogonadism unlikely
serum prolactin
Test
Check fasting levels because meals can elevate prolactin levels.
Prolactin is measured if results of testosterone and gonadotropin testing suggest secondary hypogonadism (i.e., low testosterone, accompanied by low or inappropriately normal gonadotropins).
Result
above 18 nanograms/mL is considered elevated, although much higher levels are generally present with a symptomatic pituitary adenoma
serum transferrin saturation and ferritin
Test
Check in patients with secondary hypogonadism.
Iron studies are performed to rule out hemochromatosis.
Result
elevated ferritin and transferrin saturation confirms hemochromatosis
MRI pituitary
Test
Performed to exclude pituitary and/or hypothalamic tumors or infiltrative disease.[7]
Obtain if gonadotropins (luteinizing hormone and follicle stimulating hormone) are low or inappropriately normal.
Men with serum levels of total testosterone below 150 nanograms/dL may benefit from pituitary imaging, especially when there are other supporting clinical or biochemical anomalies.[1]
Result
mass greater than 10 mm in size confirms macroadenoma; mass <10 mm in size confirms microadenoma; alternatively, may show empty or partially empty sella, or a parasellar mass
genetic testing
Test
Karyotype or copy number variation will detect Klinefelter syndrome if luteinizing hormone and follicle stimulating hormone are raised.
In men who desire fertility, Y-chromosome microdeletion analysis and cystic fibrosis transmembrane receptor (CFTR) mutations are additional tests.
Result
47,XXY confirms Klinefelter syndrome (may be mosaic)
dual-energy x-ray absorptiometry (DEXA or DXA)
Test
Long-term suppressed levels of testosterone (with correspondingly low estrogen) can lead to compromised bone health in men.
Result
hypogonadism usually causes a decrease in bone density
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