Implementation of an integrated laboratory workflow for pulmonary histoplasmosis diagnosis in a Mexican tertiary-care hospital

Background: Histoplasmosis is a systemic fungal infection caused by the Histoplasma complex, endemic in regions of the Americas, including southern Mexico.Although it is the most common endemic mycosis, it remains underdiagnosed, particularly among patients with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS), leading to increased morbidity and mortality.Timely diagnosis is essential.Objectives: The objective of this study is to describe the implementation of an integrated laboratory workflow for the diagnosis of pulmonary histoplasmosis in a tertiary-care hospital.Method: A bronchoalveolar lavage sample was analyzed, including differential testing for respiratory pathogens.Direct examination with potassium hydroxide, Giemsa staining, culture on Sabouraud dextrose agar, and urinary antigen detection using an enzyme immunoassay were performed.Results: Differential tests were negative.Extracellular and intracellular yeast within macrophages were observed.Urinary antigen testing was positive, confirming the diagnosis.Culture showed typical Histoplasma characteristics.Conclusion: The combined use of rapid and conventional diagnostic techniques enables timely identification of histoplasmosis, particularly in immunocompromised patients.