Your first testosterone blood test

Start with the question

Low libido, fatigue and weaker erections can have many causes. If you suspect low testosterone, tell your clinician what changed, when it started, and which medications you use. A result makes more sense alongside symptoms and a medical history.

Get a comparable baseline

For suspected testosterone deficiency in men who are not on therapy, the Endocrine Society recommends an accurate fasting morning total testosterone test and a repeat fasting morning measurement to confirm a low result. Tell your clinician about shift work, illness and any hormone use before scheduling.

When free T adds context

If total T is near the lower limit or a condition can alter SHBG, ask whether free T measured by equilibrium dialysis or estimated from total T, SHBG and albumin would help.

Sources

• Endocrine Society clinical practice guideline, Bhasin et al. (2018) →
• Harmonized testosterone reference interval, Travison et al. (2017) →