Blood test information
Why regular blood tests are important
Regular blood tests are essential for trans people who are self-medicating for two main reasons:
To make sure you’re on the right hormone dose. Knowing how your hormone levels compare with standard reference ranges will ensure you receive the correct dose.
If your hormone levels are lower than they should be, that could mean you’re not getting the changes you want from hormone treatment and would benefit from increasing your dosage. Likewise, if your hormone levels are higher than they should be, that could mean you’re on too high a dose and could be at risk of adverse side effects.
To spot potential problems before they occur and monitor for comorbidity (other conditions or illnesses). Feminising or masculinising hormone treatment also comes with several different risks and side effects, including:
Blood clots
Liver and kidney problems
Polycythaemia and erythrocytosis
Prolactinoma
Liver dysfunction
Heart disease
High blood pressure
Blood tests can help reduce these risks by flagging potential issues before they become serious.
The potential risk will depend on what medication you are taking, your physiology, and your family history, among other factors. For more information about the risks of hormone therapy, talk to your GP or an endocrinologist. You can also read these informed consent documents about the risks and effects of feminising or masculinising HRT.
Finding a GP to do blood tests
Your GP will be able to perform the required blood tests, you don't need to go to a specialist of any type. We have a list of helpful GPs willing to do blood tests for trans people who are self-medicating.
How often should I get blood tests?
Below is a general guideline, however, if your dose and hormone levels aren’t stabilised, 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: get a blood test one to three months after any change in dosage to monitor the effects
Blood test timings
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
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 and use gloves to apply gel for three days before your blood test)
Only blockers: have the test carried out at any time
What do I need to get tested?
Which blood tests are necessary for you will depend on many factors, and will be individualised to you and your hormone treatment. Health conditions or other medications may necessitate extra tests which you can discuss with your GP.
We give a simple guide on blood testing. Different healthcare providers and individuals may recommend similar but slightly different test lists. We have linked a few guides below so you can get a better idea of what is generally advised.
Important notes on customised blood testing:
Everyone - test estradiol (E2) and total testosterone (T) every time
If you are transmasculine - test full blood count (FBC) every time
If taking cyproterone - liver function test (LFT) and prolactin (PRL) every time
If taking bicalutamide - liver function test (LFT) every time
If taking spironolactone - test urea and electrolytes incl. potassium (U&E) every time
Recommended blood tests
General blood tests for everyone every twelve months:
Full Blood Count (FBC)
Liver Function Test (LFT)
Hemoglobin A1C (HbA1C)
Urea and electrolytes (U&E/renal function)
Cholesterol (Lipids)
Hormone tests:
Total Testosterone (T)
Estradiol (E2)
Prolactin (PRL) (mainly for transfeminine people)
Physical health checks:
Blood pressure (BP)
Weight
Other notes:
Keep personal records of all blood tests to track changes over time and monitor your response to different dosages or forms of HRT.
Dihydrotestosterone (DHT) may be of interest to some people but is unavailable through the public blood testing system, though it is available privately.
Other blood testing guides:
HSE’s National Gender Service (useful to have these tests done beforehand if you are waiting to attend)
NHS’s Gender Identity Clinic (useful to have these tests done beforehand if you are waiting to attend)
Reference ranges for hormone levels
A reference range is a set of typical or recommended values. You can compare your results against the reference ranges below to determine whether your hormone levels are normal.
You should be provided reference ranges by your GP with your test results. It's important to state whether you want female or male listed on your blood test to receive the correct reference ranges, which sometimes differ.
The reference ranges we give below may differ from the ones provided by your GP, which would generally be standard hormonal reference ranges for cis people.
Ask your GP or healthcare provider for more information if you have any doubts.
Important reference ranges
Feminising HRT:
Oestradiol (pmol/L): 400-800 (ideal level) 235-1300 (target range)
GenderGP and the Endocrine Society provide the following guidelines for estradiol levels. A range of 400-800pmol/L for estradiol is considered sufficient, but that is only half of the story; any comprehensive understanding of estradiol levels has to include testosterone levels. Injectable estrogen alone may not effectively lower testosterone production at 400pmol/L. It is best to aim for the lowest possible estrogen level that can suppress testosterone for those using injectable estrogen without blockers. Naturally, users of injectable estrogen will need higher estradiol levels than those who take pills, patches, or gel with a blocker. 800-1300pmol/L is a safer alternative for injecting without a blocker, granted that testosterone is suppressed sufficiently at the trough.
Testosterone (nmol/L): 0.3-1.7
Prolactin (MU/L): 102-496 (f) 70-400 (m)
Masculinising HRT:
Testosterone (nmol/L): 14-24
Haemoglobin (G/DL): 13-17 (m) 11.5-15 (f)
Haematocrit (L/L): 0.4-0.5 (m) 0.37-0.47 (f)
Other relevant health checks
Hormone blockers: people taking blockers but not estradiol or testosterone may need to monitor bone density.
Sexual health: clinics can vaccinate you for HPV, hepatitis A and B and screen general sexual health and STIs. You can learn more about sexual health here (Ireland, Scotland).
Breast/chest health: healthcare providers should screen breast/chest health using mammography in all people with breasts/chests in the relevant age range in line with the cis population. In those who have had a double mastectomy, healthcare providers should instead screen chest health using subareolar and periareolar annual chest examinations at the appropriate age. Find out more on Citizens Information (Ireland), the NHS (Scotland), or from your GP.
Prostate health: medical professionals should screen prostate health in those with prostates in line with the cis population at the appropriate age. Discuss with your GP for more information.
Cervical health: people with a cervix who are aged between 25 and 65 should get an HPV cervical screening test when it is due. If you are aged 25 to 29 years, you should be screened every 3 years. If you are aged 30 to 65 years, you should be screened every 5 years. Some people will need to be screened more often. Find out more on Citizens Information (Ireland), the NHS (Scotland), or from your GP.
Support:
There are online forums and websites for trans people wanting to learn more or discuss their HRT; we link a few on our healthcare resources page.
It is always important to seek qualified professional opinions before making medication changes based on online advice. However, many trans people have had to become amateur experts in hormone health, so they often have good advice if something looks particularly off.
Feedback:
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