Endocrine Society Sets the Bar for Diagnosing Low Testosterone

In 2018, the Endocrine Society published its updated Clinical Practice Guideline for testosterone therapy in men with hypogonadism, and its central message was clear: do not diagnose low testosterone based on a single lab draw or vague symptoms alone. A valid diagnosis requires symptoms and signs consistent with testosterone deficiency alongside at least two measurements of unequivocally low morning serum testosterone concentrations.

The guideline specifies that total testosterone should be measured first, with free testosterone assessed when total levels are near the lower boundary or when SHBG abnormalities are suspected. Free testosterone should ideally be measured by equilibrium dialysis or calculated using validated formulas that account for total testosterone, SHBG, and albumin. The emphasis on morning testing is critical because testosterone follows a diurnal pattern, peaking in the early hours and declining throughout the day.

The guideline also draws a line between primary hypogonadism, where the testes themselves are failing, and secondary hypogonadism, where the problem originates in the pituitary or hypothalamus. Distinguishing between these requires measuring LH and FSH concentrations, a step that many clinicians skip but that fundamentally changes the treatment approach.

Importantly, the Endocrine Society recommends against routine screening of men in the general population. Testing should be driven by clinical suspicion, not by marketing. This makes it even more important for men who do have symptoms to bring organized, longitudinal health data to their provider rather than relying on a single conversation to trigger the right workup.

The Tracking Connection

Kairos™ helps men meet the evidentiary standard these guidelines demand. By tracking symptoms, energy levels, mood, and prior lab results over time, Kairos creates a clinical narrative that makes it easier for providers to identify who genuinely needs testing and follow through with the two-measurement protocol. Instead of walking into an appointment with a hunch, you walk in with a data-backed case.