Landmark study defines normal ranges for testosterone levels

January 10, 2017

A large study of more than 9,000 men has established harmonized reference ranges for total testosterone in men that when applied to assays that have been appropriately calibrated will effectively enable clinicians to make a correct diagnosis of hypogonadism, according to a new study published in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism.

Testosterone is the main sex hormone in men, though women have as well in smaller amounts. Hypogonadism, a condition characterized by , can lead to sexual dysfunction, decreased muscle and bone strength, less energy, and lower fertility. The and effective treatment and prevention of hypogonadism as well as many other diseases depend on accurate measurement of hormones, but lack of both defined reference ranges of testosterone and standardization of hormone assays has made diagnosing hypogonadism a difficult task.

"Well-defined reference ranges are at the heart of clinical practice and without them clinicians can make erroneous diagnoses that could lead to patients receiving costly, lifelong treatments that they don't need or deny treatments to those who need them," said Shalender Bhasin, MD, of Brigham and Women's Hospital, Harvard Medical School in Boston, MA and lead author of the study. "Our data establish a reference range for testosterone. These data also show that variations in assays is an important contributor to variation in testosterone levels in cohorts from different geographic regions. Clearly we need standardization in all hormone assays."

In this study, researchers obtained serum testosterone samples from men who had already had their assayed locally. The samples were sent to the Centers for Disease Control and Prevention's (CDC) Clinical Standardization Programs at the National Center for Environmental Health where testosterone concentrations were measured using a higher order liquid chromatography tandem mass spectrometry method.

Researchers used the results from both measurements to generate harmonized values, which were in turn used to derive standardized, age-specific reference ranges overall. The harmonized normal range for testosterone in a non-obese population of European and American Men, 19-39 years, is 264-916 ng/dL.

"Without harmonized reference ranges and standardized assays, tests can lead to misdiagnoses and unfortunately this happens every day around the world," said Hubert Vesper, PhD who is also a co-author of the study and co-chair of The Partnership for the Accurate Testing of Hormones (PATH). "Now we have a reference range for testosterone, and it's important that we take this into consideration in the tests that clinicians and patients depend on for accurate diagnoses."

PATH provides technical and scientific support to the CDC Steroid Hormone Standardization Program, conducts educational activities on hormone measurement, and advocates for the universal use of standardized hormone tests, where available.

Explore further: Doctors urged to be cautious when treating low testosterone

More information: "Harmonized Reference Ranges for Circulating Testosterone Levels in Men of Four Cohort Studies in the USA and Europe," DOI: 10.1210/jc.2016-2935

Related Stories

Doctors urged to be cautious when treating low testosterone

August 30, 2016

Doctors have been advised to exercise caution when prescribing testosterone treatment for older men with low testosterone and a history of cardiovascular disease, according to a position statement published today in the Medical ...

Testosterone therapy fails to treat ejaculatory dysfunction

July 9, 2015

Men who have ejaculatory disorders and low testosterone levels did not experience improved sexual function after undergoing testosterone replacement therapy, according to a new study published in the Endocrine Society's Journal ...

Recommended for you

Exercise and vitamin D better together for heart health

April 27, 2017

Johns Hopkins researchers report that an analysis of survey responses and health records of more than 10,000 American adults for nearly 20 years suggests a "synergistic" link between exercise and good vitamin D levels in ...

'Diet' products can make you fat, study shows

April 25, 2017

High-fat foods are often the primary target when fighting obesity, but sugar-laden "diet" foods could be contributing to unwanted weight gain as well, according to a new study from the University of Georgia.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.