We use cookies to understand how you use our site and to improve your experience. This includes personalizing content and advertising. To learn more, click here. By continuing to use our site, you accept our use of cookies. Cookie Policy.

Features Partner Sites Information LinkXpress hp
Sign In
Advertise with Us
LGC Clinical Diagnostics

Download Mobile App




Diagnostic Accuracy of Histoplasma Urine Antigen Assay Evaluated

By LabMedica International staff writers
Posted on 29 Nov 2018
Print article
Image: The ALPHA Histoplasma Enzyme Immunoassay (EIA) test kit (Photo courtesy of IMMY).
Image: The ALPHA Histoplasma Enzyme Immunoassay (EIA) test kit (Photo courtesy of IMMY).
Histoplasmosis is an endemic mycosis in many regions of Latin America. In the human immunodeficiency virus (HIV) infected population it manifests as progressive disseminated histoplasmosis (PDH), an entity hard to diagnose since the causative fungi, Histoplasma capsulatum, is slow growing and requires advance biosafety for its handling.

The standard of reference for PDH diagnosis is the isolation of Histoplasma capsulatum from a non-respiratory sample, typically bone marrow or peripheral blood, or the visualization of yeast-like structures in the histopathologic examination. In the USA, histoplasmosis is also endemic, and its PDH presentation is commonly diagnosed by the detection of Histoplasma urine antigen (HUAg).

Scientists at The National Institute of Medical Sciences and Nutrition Salvador Zubirán (Tlalpan, Mexico City, Mexico) conducted a multicenter, prospective, diagnostic test study in two secondary and eight tertiary-care facilities from seven states of Mexico, from December 2015 to October 2017. At least 5 mL of peripheral blood were inoculated in a BD BACTEC Myco F/ Lytic vial; for bone marrow aspirates, a similar amount (5 mL) was inoculated in a BACTEC Myco F/ Lytic and a BACTEC Peds Plus F (3 mL), and 1 mL in a Löwenstein-Jensen and Sabouraud solid media.

The team evaluated the diagnostic accuracy of IMMY ALPHA Histoplasma Enzyme immunoassay (EIA) Test Kit. The scientists included 288 cases for this analysis. From these patients, the central laboratory processed 1,068 samples: 277 blood cultures, 252 bone marrow aspirate cultures, 104 biopsies for tissue culture, 147 biopsies for the histopathologic examination, and 288 urine samples for HUAg detection. They classified 85/288 (29.5%) patients as PDH–proven, 28.2% (24/85) based on positive histopathologic examination and positive culture, 58.8% (50/85) by positive culture only and 12.9% (11/85) by positive histopathologic exam only. The sensitivity of ALPHA-HUAg was 67.1% (95% CI, 56–76.8%) and the specificity was 97.5% (95% CI, 94.3%-99.1%). The positive likelihood ratio was 27.2 (95% CI; 11.6–74.4). In 10.5% of the PDH–proven patients, a co-existing opportunistic infection was diagnosed, mostly disseminated Mycobacterium avium complex infection.

The authors concluded that ALPHA-HUAg is a useful test for the diagnosis of PDH, in patients with high level of suspicion in endemic regions for H. capsulatum, and may favor early targeted-antifungal treatment, thus improving the prognosis of these frail HIV-patients. Nevertheless, the culture-based approach should ensue simultaneously since co-infections are frequent and a negative result of ALPHA-HUAg does not discard PDH in patients from endemic regions for H. capsulatum. The study was published on November 5, 2018, in the journal Public Library of Science Neglected Tropical Diseases.

Related Links:
National Institute of Medical Sciences and Nutrition Salvador Zubirán

Gold Member
Veterinary Hematology Analyzer
Exigo H400
Verification Panels for Assay Development & QC
Seroconversion Panels
New
Respiratory QC Panel
Assayed Respiratory Control Panel
New
Toxoplasma Gondii Immunoassay
Toxo IgM AccuBind ELISA Kit

Print article

Channels

Molecular Diagnostics

view channel
Image: Researcher Kanta Horie places a sample in a mass spectrometer that measures protein levels in blood plasma and other fluids (Photo courtesy of WashU Medicine)

Highly Accurate Blood Test Diagnoses Alzheimer’s and Measures Dementia Progression

Several blood tests are currently available to assist doctors in diagnosing Alzheimer's disease in individuals experiencing cognitive symptoms. However, these tests do not provide insights into the clinical... Read more

Microbiology

view channel
Image: Schematic representation illustrating the key findings of the study (Photo courtesy of UNIST)

Breakthrough Diagnostic Technology Identifies Bacterial Infections with Almost 100% Accuracy within Three Hours

Rapid and precise identification of pathogenic microbes in patient samples is essential for the effective treatment of acute infectious diseases, such as sepsis. The fluorescence in situ hybridization... Read more
Copyright © 2000-2025 Globetech Media. All rights reserved.