Blood tests

Why?

Doing regular blood test are essential for two reasons:

• Making sure your levels of hormones are correct. If the definition of “correct” regarding hormone levels varies from individuals, having a number makes you more able to estimate if you are underdosed or overdosed. Taking a blood test when you feel at your best and experience the changes you seek lets you know what levels of hormones are good for you.
• Preventing potential problems, that have to do (or not!) with your new hormonal balance. These includes:
• Blood clots
• Liver and kidney problems
• Polycythaemia/erythrocytosis (high red cells in blood)
• Prolactinoma
• Liver dysfunction
• Heart disease
• High blood pressure

When?

Below is a general guideline, however, if your dose and hormone levels aren’t stabilized, get a blood test every three months until it is, before reducing the frequency.

• Baseline test before starting hormone treatment: an initial blood test before starting HRT is beneficial for establishing your baseline hormone levels and screening for morbidity (illnesses)

• Three months: after three months of hormone treatment, get your second blood test

• Six months: after six months, get your third blood test

• Twelve months: after twelve months of hormone treatment, get your fourth blood test

• Every year after: get a blood test every six to twelve months for as long as you take hormone treatment

• Change in dosage and administration route: get a blood test one to three months after any change in dosage to monitor the effects, and after changing administration route calibrate dosage. Wait at least a month after changing to a new route of administration before taking the test.

Timings for blood tests vary depending on the way in which your medication is administered.

• Estradiol injections: have the test carried out immediately before your next injection, and 1 month at least after the 1st injection
• Testosterone undecanoate injections: have the test carried out immediately before your next injection
• Testosterone enanthate/cypionate injections: have the test carried out midway between injections
• Patches: have the test carried out the day after a patch change
• Gels: have the test carried out 4-6 hours after gel application (to avoid contamination don’t apply gel on the lower arms for at least a week before your blood test)

What?

A complete blood work should include these. Other values might be added depending on your own health profile, and medication.

• Full blood count
• Blood biochemistry: Glycemy, Plasma aspect, Creatinine…
• Ionogram: Sodium, Potassium…
• Lipids: Cholesterol, Triglycerides
• Liver enzymes: ALAT, ASAT, GGT
• Sex hormones and affiliated: FSH, Testosterone, Estradiol, Progesterone, Prolactin
• Possibly, thyroid hormones: TSH

Refer to our description of each medication to know which values are particularly important to monitor for you.

Total, free, and bioavailable testosterone

Note that when measuring testosterone, the standard measurement is usually total testosterone, as it is easier and cheaper to measure. As explained in the section on SHBG, testosterone binds itself to albumin and SHBG, which makes it unable to bind to the androgen receptors, and blocks its effect. The rest - a tiny portion of around 1-2% - is “free” and biologically active. You can ask for measuring the “bioavailable” testosterone, which is the addition of the free testosterone and the albumin bound testosterone, since the binding with albumin is loose enough that testosterone can easily unbind and become biologically active. However, especially for transfeminine people, the total testosterone value is usually a good indicator of the efficacy of your treatment, and a total testosterone under 50 ng/dl corresponds to nearly nothing in bioavailable testosterone. You can also ask to measure your SHBG levels, especially if your treatment gives you good levels of sex hormones, but still no effects after a while. Abnormally high SHBG levels could be a cause. You can refer to our page on SHBG for more details.