Lab Values in Transgender People
A question that we have been seeing more of is about lab values in transgender people. I’m here to share some basics about laboratory measurement in trans men and trans women, since there’s been an increase in literature over the past few years.
Transgender people will typically take either estrogen or testosterone in addition to some other medications during transition. We call this ‘gender-affirming therapy’. This helps trans men and trans women achieve the appearance and secondary sexual characteristics of the gender they are transitioning to.
For trans men, testosterone helps develop facial hair, voice changes, and changes in physique. Testosterone redistributes fat into a more typical male physique, and is linked to increases in sexual desire.
For trans women, estrogen helps redistribute fat into a feminine physique and lowers growth of facial and body hair. Trans women often take a medication called spironolactone, which helps with breast development and suppresses the effect of testosterone.
Lab Measurement of Sex Hormones for Transgender People
Measuring sex hormones is important for transgender people. It’s important to keep value in a normal range to prevent side effects from occurring- for instance, estrogen in trans women is linked to blood clots. Keeping levels in a normal range can help prevent this. 
In the first year after beginning hormone therapy, transgender people typically have labs drawn every three months to check estrogen and testosterone levels. After this, if there aren’t any issues with levels being too high or too low, they can decrease lab monitoring to once or twice a year .
Transgender women should try to keep their testosterone less than 50 ng/dL. Estradiol should be kept between 100-200 pg/mL.
For transgender men, testosterone levels should be kept between 400-700 ng/dL.
Our own Lab Test Analyzer is a great way to monitor levels of sex hormones over time.
Other Lab Considerations
Some other lab values that are known to change in transgender people are creatinine and hemoglobin. The data we have shows that over time, transgender people taking hormone therapy will eventually have lab values that match their cisgendered counterparts.
Testosterone raises red blood cell count and also raises hemoglobin. In trans men, a stable increase in hemoglobin is usually seen in 6-9 months. For trans women in whom testosterone is being suppressed, a drop in hemoglobin is noted in about 3-6 months [3, 4, 5].
Creatinine is a protein found in the blood that rises based on muscle mass. It’s usually higher in men than women. For trans men taking testosterone, creatinine rises to a cisgendered male level in about 9 months. For trans women, creatinine drops at a faster rate- they usually reach a stable level close to cisgendered women in about 3 months [3, 5].
There are also side effects for people taking spironolactone, which is generally taken by trans women. People taking this medication may have an elevation in potassium or a decrease in their blood pressure.
Trans folks are one of many groups that benefit from close laboratory monitoring, especially over the course of the first year when starting hormone therapy. It’s important to monitor hormone levels to prevent side effects.
We live in an exciting time where it’s more possible for people to become their authentic selves. The growing body of data we have about transgender peoples’ labs changing over time is a way in which we, as a scientific community, show that we invest in and care about everyone. I’m happy to be able to share this information with you!
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