Gender-affirming hormone therapy markedly impacts the results of common laboratory tests for transgender patients. This is according to a study that underscores the need for transgender-specific reference intervals to ensure this underserved population receives accurate diagnoses and effective treatments.
The fact that many medical protocols do not account for sex/gender incongruence is a significant barrier for transgender individuals seeking healthcare. In particular, for the nearly 50% of transgender individuals on hormone therapy, the medical field has yet to define reference intervals, which are the ranges of test result values observed in a healthy population that are used to determine whether individual lab results are normal or concerning.
Without tailored reference intervals, test results for transgender patients on hormone therapy could indicate an underlying condition but go unrecognized if they are considered normal for cisgender individuals (those whose gender matches their assigned-at-birth sex). Conversely, if lab results for transgender patients fall outside of cisgender reference intervals, they could trigger unnecessary follow-up work even if the results are actually normal.
To help build the case for developing transgender reference intervals, a research team led by Jeff SoRelle, MD, of University of Texas Southwestern Medical Center in Dallas, investigated whether transgender patients on hormone therapy exhibit altered results for laboratory tests ordered during yearly check-ups. The study authors recorded lab values for a complete blood count, comprehensive metabolic panel, and lipid tests in 264 healthy transgender patients undergoing hormone therapy in transgender clinics from 2007 to 2017. Of these patients, 133 were taking estradiol to transition from male to female, and 89 were taking testosterone to transition from female to male. The scientists also gathered lab results for 149 transgender patients not undergoing hormone therapy to serve as a point of comparison.
From this, the researchers determined that both transgender women and men taking hormones displayed altered values for measures of red blood cell, kidney, and liver health. Transgender women taking hormones also had altered sodium, calcium, total protein, glucose, and platelet levels, while transgender men taking hormones displayed altered lipid values. Interpretation of these altered test results in the context of cisgender reference intervals could have serious consequences, from preventing diagnosis of anemia or kidney disease to affecting assessment of cardiovascular disease risk.
“Transgender patients will need their own reference ranges for several important parameters such as hemoglobin and creatinine,” said SoRelle. “It will also be important to determine whether proteins from cardiac muscle or the prostate, such as troponins or prostate specific antigen, are altered, too, which could affect diagnosis of heart attacks and prostate cancer.”