Laboratory values need context
There is no single perfect testosterone number.
Total testosterone varies with age, time of day, assay, health, medication, sleep, and other factors. A chart gives context, not a diagnosis.
Reference-band context
Why this is not a “low T test”
Clinical interpretation can require symptoms, properly timed testing, repeat confirmation, and the laboratory’s validated assay and range.
- Results can vary by time of day.
- Acute illness and poor sleep can matter.
- Medications and health conditions can matter.
- Total and free testosterone answer different questions.
Reference sample
Total testosterone by age
Illustrative Endotext data measured by HPLC–MS/MS in normal men. Some age groups have modest sample sizes.
5th percentileMean95th percentile
Do not start, stop, or change medication based on this chart.
Harmonized younger-adult study
264–916 ng/dL
A harmonized reference interval reported for healthy, non-obese men ages 19–39. It is not a universal pass/fail rule for every laboratory or person.
Bring better questions to the appointment
- Was the sample taken at the recommended time?
- Should the test be repeated?
- Which symptoms actually fit a hormone problem?
- Could another condition or medication explain them?