Longest-duration study of how transgender hormone therapy alters medical test results featured at the 71st AACC Annual Scientific Meeting

Groundbreaking research presented at the 71st AACC Annual Scientific Meeting & Clinical Lab Expo has revealed how transgender hormone therapy affects the results of common laboratory tests in the long term. This first-of-its-kind study could enable the development of transgender-specific reference intervals, which are crucial to ensuring that transgender patients get accurate diagnoses and equitable healthcare.

All major medical associations agree that transgender individuals need to be able to express their gender in ways that make them feel comfortable, and for many of these individuals, this involves physically changing their body through hormone therapy. However, research presented in 2018 at the 70th AACC Annual Scientific Meeting showed that 6 months of transgender hormone therapy markedly changes results for common laboratory tests. This finding demonstrates a critical need for transgender-specific reference intervals, which are the ranges of lab values observed in a healthy population that are used to determine whether individual lab results are normal or concerning. Without these reference intervals, clinicians could misinterpret transgender patient test results, which in turn could lead to serious health consequences as a result of misdiagnosis and/or inappropriate treatment.

The researchers behind the 2018 study—a team led by Jeffrey SoRelle, MD, of the University of Texas Southwestern Medical Center in Dallas—have now completed a follow-up study that lays the foundation for establishing transgender-specific reference intervals. SoRelle’s team tracked comprehensive metabolic panel, complete blood count, and lipid test results for 147 healthy transgender patients on hormone therapy over the course of 5 years. This is the longest time that any study has monitored lab values in transgender individuals to date.

Out of all the test values the study examined, red blood cell and creatinine levels (a measure of kidney health) underwent the largest shifts when transgender individuals started hormone therapy. These values then typically stabilized after 6 months. In transgender women specifically, platelet and low-density lipoprotein levels (a measure of cardiovascular health) increased after several years of hormone therapy, while alkaline phosphatase (a marker of liver and bone health) decreased steadily for a few years before returning to baseline levels in the long term. Knowledge of these trends could greatly improve healthcare providers’ ability to interpret transgender patients’ results for routine lab tests, and to monitor these patients for conditions ranging from anemia to heart disease and kidney failure.

“When test results are sent to clinicians, they are interpreted by reference intervals, but not having a set of reference intervals to reflect how hormone therapy changes lab values for transgender individuals can lead to faulty diagnoses or overlooked abnormalities,” SoRelle said. “If a transgender woman’s red blood cell count is evaluated based on the reference interval for men, for example, she could be misdiagnosed with anemia.” These findings are therefore a huge leap forward for transgender healthcare. “For the first time, clinicians have a granular description of how and when transgender hormone therapy changes lab values, as well as how these values stabilize in the long term.”

Session Information

Abstract A-166: Long-Term Effect of Hormone Therapy on Lab Values in Transgender Individuals will be presented during the following three sessions:

• AACC Student Poster Contest (Part 1): Oral Presentations Monday, August 5, 1 – 2 p.m., Room 201AB
• ePoster Session: Endocrinology Tuesday, August 6, 11:30 a.m. – 12:15 p.m., Exhibit Hall
• Scientific Poster Session Tuesday, August 6, 9:30 a.m. – 5 p.m., (presenting author in attendance from 12:30 – 1:30 p.m.) Exhibit Hall

All sessions will take place at the Anaheim Convention Center in California.