How to order a serum testosterone level test?

From the Guidelines

To order testosterone levels, you should first consult with your healthcare provider who can write a laboratory requisition for a morning serum testosterone level, as recommended by the most recent guidelines 1. When ordering testosterone levels, it is essential to consider the timing of the test, as testosterone levels naturally fluctuate throughout the day.

• The most common test is total testosterone, which should ideally be drawn in the morning (between 7-10 AM) when levels are naturally highest.
• Your doctor may also order free testosterone, bioavailable testosterone, or sex hormone binding globulin (SHBG) for a more complete picture, especially if total testosterone levels are close to the lower limit 1.
• You'll need to fast for 8-12 hours before the test, and avoid biotin supplements for at least 72 hours prior.
• The blood draw is a simple procedure that takes just a few minutes at a laboratory or clinic.
• Some providers may recommend testing on two separate mornings to confirm results, especially if making treatment decisions.
• Certain medications like steroids, opioids, and some seizure medications can affect results, so inform your doctor about all medications you're taking.
• Normal testosterone ranges vary by age and sex, and your doctor will interpret the results based on your specific situation and symptoms, taking into account the potential benefits and risks of testosterone replacement therapy, as outlined in the recent guidelines 1.

From the FDA Drug Label

Prior to initiating testosterone gel, confirm the diagnosis of hypogonadism by ensuring that serum testosterone has been measured in the morning on at least two separate days and that these concentrations are below the normal range To order testosterone levels, measure serum testosterone in the morning on at least two separate days.

• Key steps:
  • Measure serum testosterone in the morning
  • Measure on at least two separate days
  • Ensure concentrations are below the normal range 2 2

From the Research

Ordering Testosterone Levels

To order testosterone levels, the following steps can be taken:

• Measure morning total testosterone level by a reliable assay as the initial diagnostic test 3
• Confirm the diagnosis by repeating the measurement of morning total testosterone and in some patients by measurement of free or bioavailable testosterone level, using accurate assays 3, 4, 5
• Measure testosterone levels in 2 or more fasting samples obtained in the morning 4, 5
• Use a reliable assay, such as liquid chromatography-tandem mass spectrometry, in a laboratory certified by an accuracy-based program 4, 5
• Ideally, measure free testosterone level by equilibrium dialysis method 4, 5

Considerations for Measurement

• Testosterone levels should be measured in a fasting state in the morning 4, 5
• Reference ranges for total testosterone can be applied to laboratories certified by the HoST Program 4
• Free testosterone levels should be measured in men in whom alterations in binding protein concentrations are suspected or in whom total testosterone levels are only slightly above or slightly below the lower limit of the normal male range for testosterone 5
• The evaluation and management of male hypogonadism should be based on symptoms and on serum testosterone levels 6, 7

Clinical Practice

• Clinical practice guidelines recommend that testosterone levels be measured on ≥2 occasions to confirm a diagnosis of hypogonadism 7
• Gonadotropins should be measured to determine whether hypogonadism is primary or secondary 7
• Testosterone levels should be measured to monitor the adequacy of testosterone therapy 7
• However, the use of hormone testing as recommended by guidelines is not always routinely performed in real-world clinical practice 7