What a testosterone blood test should answer
Testosterone levels vary through the day and can be affected by sleep, illness, calorie restriction, medications, and recent training load. For that reason, medical guidance generally favours morning testing and repeat confirmation when results are low or borderline.
Blood testing should also help answer whether low testosterone is likely to be primary, secondary, or related to wider health factors. Depending on the clinical picture, a doctor may review total testosterone, free testosterone or SHBG, LH, FSH, prolactin, full blood count, liver and kidney markers, lipids, HbA1c, thyroid function, PSA where appropriate, and other safety markers.
Monitoring during treatment
If testosterone therapy is prescribed, monitoring is part of safe care. Follow-up blood tests help assess testosterone exposure, haematocrit, PSA where relevant, cardiovascular risk markers, liver and metabolic health, symptoms, side effects, and whether dose or formulation changes are needed.