How effective is blood test for low testosterone?

Testosterone changes through the day and can be affected by poor sleep, acute illness, weight changes, intense exercise and some medicines. A clinician may therefore request an early-morning sample and repeat a low result before discussing treatment. Total testosterone may be assessed with related hormones, and sometimes free testosterone, to explore how the body is making and using the hormone. A single low reading does not identify the cause.

Follow the laboratory instructions and tell the clinician about the collection time, sleep, illness, medicines, supplements and any hormone treatment. Describe changes in sexual desire, erections, energy, mood, muscle strength, fertility or testicular health. Further hormone tests may help distinguish a problem in the testes from one involving the pituitary or hypothalamus. Do not begin testosterone without medical assessment, particularly if fertility matters.

Seek urgent help for sudden severe headache with vision changes, fainting, chest pain, severe breathlessness or sudden testicular pain. Arrange a timely appointment for marked loss of energy, rapid physical changes, breast enlargement, infertility concerns or symptoms that are worsening. These concerns may need broader assessment than a testosterone result alone.

Ask when the sample should be taken, whether a low result needs repeating, which related hormones should be checked, and what cause is being considered. Ask how treatment could affect fertility, sleep, prostate monitoring and other medicines before making a decision.