Impact of Gender Affirming Hormone Therapy on Hematological Values of Transgender and Gender Diverse Patients

Purpose It is recognized that sex hormones, including gender affirming hormone therapy (GAHT), affect the rate of erythropoiesis, demonstrated in complete blood count (CBC) measurements. While exogenous hormonal impact is understood, established reference ranges are based on sex assigned at birth, signifying endogenous hormone states. Leading organizations providing GAHT guidelines recommend using affirmed gender when assessing laboratory values. This study sought to further the understanding of the impact GAHT may have on hematological values through a statistical comparison of gendered adult laboratory values and population means. Methods A retrospective chart review of patients who received transgender healthcare at an urban university health system was performed. Electronic medical record documentation of transgender and gender diverse (TGD) patients on GAHT, meeting study criteria, allowed for categorical analysis of transmasculine and transfeminine cohort hematological laboratory values and comparison to adult cisgender laboratory derived population means. Results Criteria for analysis was met for 139 transmasculine and 57 transfeminine patients. Data identified statistically significant difference in transmasculine cohort red blood cell (RBC) means as well as hematocrit (Hct) means from those of both established cisgender male and cisgender female adult laboratory derived population mean values. Conclusions An advanced understanding of the impact of GAHT on common laboratory values is critical. Transmasculine RBC and Hct means existing between laboratory established adult cisgender male and cisgender female population means may impact the proper diagnosis and treatment of hematological based clinical conditions. Further research studies on hematological laboratory values of the TGD population may improve the equity and quality of care received.