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Estrogen HRT labs
Estrogen HRT labs

The Deal with Estrogen Labs

Written By

FOLX Clinicians

Dec 5, 2020

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Why do we need labs?

Hormones are the body’s chemical messengers, and hormone replacement therapy (HRT) is essentially kicking off a whole new slew of chemical signals to the body by traveling through the bloodstream to different tissues and organs to tell them what kind of work they need to do or stop doing.

Because HRT is introducing something new to the chemical makeup of bodies, labs are used to monitor safe hormone levels and effects, and to make sure bodily changes are aligned with what each person wants from their HRT regimen (both with and without taking anti-androgens). When our clinicians order labs for those on estrogen, we’re testing for a couple things.

First things first, we test estradiol (estrogen) levels.

An estradiol lab checks the amount of estradiol (the most commonly prescribed estrogen) in the bloodstream, which is ultimately what’s available for the body to use and create bodily changes like skin softening, fat redistribution, breast growth. Based on the individual taking estradiol, they may desire slower or quicker bodily changes which may be impacted by dose (more on that here), this test is one of the factors that helps determine if the current dosage is right for the desired speed of change, or if adjustments should be made to dose.

While fairly uncommon given the types of estrogen we use for HRT, high levels of estrogen can increase risks for blood clots, which in turn, can lead to risk for stroke or heart attack, so it’s crucial to keep an eye on this. Most of the data on these risks is drawn from studies of cisgender women on hormonal birth control or postmenopausal hormone replacement therapy.

We check the (decreased) testosterone levels.

We check testosterone levels for essentially the same reason as estrogen levels -- to assess when someone’s individual target range has been reached and can be maintained. Almost every body has both estrogen and testosterone hormones, and HRT simply changes which is at a higher level in the body. So Estrogen HRT doesn’t deplete the body of testosterone, it just lowers it, meaning we still keep an eye on it. A testosterone test checks how well suppressed, or low, the testosterone levels are in the bloodstream. Whether someone is on estradiol & a testosterone-blocker, just estradiol, or just a testosterone-blocker, we order this test.

And we watch out for potassium levels for folx on spironolactone, too.

For those taking spironolactone, we also require testing for potassium levels. The kidneys generally do a good job keeping potassium levels down by removing excess potassium from the blood. However, since spironolactone is considered a ‘potassium-sparing medication’ (tells your body to hold on to potassium instead of excrete it out through urine), we need to keep an eye on your potassium levels while you are on spironolactone. While rare, if the potassium levels are too high, it can mean hyperkalemia, a dangerous condition that can cause irregular heartbeat, trouble breathing, and paralysis.

What about all the other labs that some providers run?

At FOLX, we run standard labs associated with HRT to assess hormone levels, as well as labs to monitor the direct impact hormones can have on your health. We want to only run labs that are necessary for the care we are providing so we can keep costs low for members. We do not run other labs such as: lipid panels, A1C (to check for diabetes), CBC (complete blood count) or CMP (comprehensive metabolic panels). Some folx may have other medical conditions that may benefit from closer lab evaluation -- we review some of those conditions in our Informed Consent process so that folx can make their own decisions how to proceed. 

At this point, FOLX is not offering primary care. However, we are happy to help you find a primary care provider to help you monitor any other medical conditions.

FOLX pairs lab results with our members’ lived experiences to come to final medical decisions.

At FOLX, we do not base medical decisions solely on labs. It is much more important to hear from our members about how they are feeling. We will communicate with our members about any lab results, and if there are any concerns from a medical perspective, but we do not adjust dosages just based on what a lab result says. We want to hear from the members themselves about what feels right in their body and how they want to move forward before finalizing any changes.

Lab results can vary based on estrogen route.

It can be a bit harder to measure an accurate level of estrogen in the bloodstream for people who take weekly or biweekly injections, because the level of estrogen goes up quite high right after the injection, and drops down a bit lower coming up to the next injection. Therefore it’s recommended folx on injectable estradiol try to schedule labs around half-way between injections, or at the end of the injection cycle to get the most accurate results. 

For those on daily forms of estradiol such as patches or pills, folx can still have some fluctuation in levels, but they’ll be a bit less drastic than those on injectable. (Read up more on estrogen routes here.)

Labs need to happen more frequently when starting or restarting estrogen.

As folx are starting estrogen, or coming back to it after a long break or lapse in care, we need to monitor their testosterone and estrogen levels every three months. After typically two-to-four rounds of labs, folx generally find their resting dose, which is the dose that suits their body and their desired speed of change. From there on out, we generally recommend labs every year, for however long folx are on estrogen, just to keep an eye on things and adjust if needed.

FOLX wants to make getting labs done easy.

Presently, FOLX is able to order labs sent to members’ nearest Quest Diagnostics PSC (Patient Service Center). The Quest Diagnostics test requires going in-person and having a vial of blood drawn through a needle. Important to know if you choose to go to Quest -- they are required to use members’ legal names on the lab requisition form, which can be uncomfortable for some, and can lead to Quest technicians using deadnames or incorrect pronouns, as well as encountering unpredictable nonbinary- and trans-competency and sensitivity among technicians. Unfortunately, this is the widest reaching network of in-person labs to support our telehealth care. We are working to improve lab testing for our members, but we wouldn’t feel right not sharing this.

Finally, for those switching over to FOLX for HRT care, we are able to accept estrogen and testosterone labs that were drawn within the last year, as long as they were done while on the same route and dosage requested from FOLX. One less needle!

So, that’s that on that for estrogen labs. For those ready to get started with FOLX for estrogen, the process begins here. For existing FOLX members with additional questions about labs, don't hesitate to schedule time with a clinician. And for those who’ve just got some more questions, read up on estrogen here, and feel free to reach out to us at

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