How a TRT Assessment Works in Australia

Testosterone follows a daily rhythm and is highest in the morning, and levels can vary meaningfully from day to day. Endocrine Society of Australia and RACGP-aligned guidance reflects this: a single low reading isn't considered diagnostic on its own. The expectation is two separate morning, fasted total testosterone measurements before anyone draws a conclusion.

This is a deliberate safeguard against over-diagnosis — a single low result on a bad day, taken in the afternoon, or after a poor night's sleep can look like hypogonadism when it isn't.

Total testosterone alone doesn't tell a doctor why a result is low, so a proper panel typically also looks at:

LH and FSH — pituitary hormones that drive testicular testosterone production. High LH/FSH with low testosterone points toward a testicular (primary) cause; low or inappropriately normal LH/FSH with low testosterone points toward a pituitary or hypothalamic (secondary) cause.

SHBG (sex hormone-binding globulin) — determines how much testosterone is bound versus biologically available. Two men with identical total testosterone can have very different free testosterone depending on SHBG, so this marker helps a doctor interpret the total testosterone number correctly rather than at face value.

Prolactin — an elevated result can suppress testosterone production and, in some cases, points toward a pituitary issue that needs to be investigated in its own right before any hormone-related decision is made.

Together, these markers help a doctor rule in or rule out hypogonadism and identify a likely cause. What they don't do is authorise treatment — that decision, including whether testosterone therapy is appropriate at all, sits entirely with the assessing doctor based on the full clinical picture, not on a pathology result in isolation.