Between Biological Sex and Lived Gender: Considerations for The Interpretation of Laboratory Tests in Transgender Patients
Abstract
Gustavo Queiroz Sampaio, Ana Cristina da Silva Pinto, Suzy Christine Goes de Melo Martins, Eduardo da Costa Martins and Gabrielle Araujo de Melo
The interpretation of laboratory tests in transgender patients requires a critical understanding of the interactions between biological sex, lived gender, and gender-affirming therapies. Natural and treatment-induced hormonal variations can alter laboratory parameters in a way that compromises diagnoses if conventional criteria based on natal sex are applied without adjustment. The overall objective is to understand how biological sex, gender identity, and medical-hormonal interventions influence laboratory results, proposing interpretative guidelines for clinical practice. This study is an integrative literature review of the Google Scholar, SciELO, and LILACS databases, covering the period from 2020 to 2025. Original studies, reviews, and undergraduate theses in Portuguese that addressed biochemical, hematological, and hormonal alterations in transgender individuals, with or without hormonal therapies, were included. Inclusion criteria considered methodological quality and clinical relevance; data selection and extraction followed a systematic process with double reading. The results indicate significant changes in lipid profiles, liver markers, hemoglobin, and sex hormones after estrogen or androgenic therapies. Conventional reference ranges often do not reflect the variability observed in transgender individuals, especially during transitional phases. Studies highlight the need to record legal sex, birth sex, type, and duration of hormone therapy for contextualized interpretation. Given the above, it is recommended that laboratory practices be adopted that incorporate hormonal history and gender identity, specific reference ranges be developed, and continuing education for professionals be provided. Longitudinal research and methodological standardization are urgently needed to reduce diagnostic biases and promote safe and inclusive care and participation of the transgender community.