# P-257. Performance of Serum Cryptococcal Antigen for Early Detection of Cryptococcal Meningitis in People Living with HIV

## TL;DR

This study evaluates serum cryptococcal antigen screening for early detection of cryptococcal meningitis in HIV patients and finds it increases diagnosis rates but does not reduce hospital mortality.

## Contribution

The study demonstrates the effectiveness of serum cryptococcal antigen screening in identifying cryptococcal meningitis in hospitalized HIV patients.

## Key findings

- Serum cryptococcal antigen screening increased lumbar puncture rates and meningitis diagnoses in HIV patients.
- Cryptococcal meningitis was diagnosed in 15.5% of patients, more frequently in those with positive serum antigen results.
- Despite early treatment, hospital mortality rates remained unchanged between groups.

## Abstract

The development of cryptococcal antigen (CrAg) detection methods, such as latex agglutination, ELISA, and lateral flow assays has significantly improved early diagnosis, achieving sensitivities and specificities between 99.1% and 100% (1-4). This study aimed to assess the utility of serum CrAg (SCrAg) screening and subsequent early treatment in reducing in-hospital mortality among people living with HIV (PLHIV) in a teaching hospital.

We conducted a descriptive, retrospective, cross-sectional, and analytical study of adults (≥18 years) living with HIV who were hospitalized in clinical stage C for any reason between December 2021 and June 2023 at the University Hospital “Dr. José Eleuterio González.” Clinical and laboratory data were collected from hospital records. Qualitative serum and CSF cryptococcal antigen (CrAg) were detected using the Cryptococcal Antigen Latex Agglutination System (Meridian Bioscience®). All patients with a positive serum CrAg (SCrAg) result underwent lumbar puncture for cytochemical analysis, India ink staining, microbiological culture, and CSF CrAg testing.

A total of 129 people living with HIV (PLWHIV) were included in the study, of whom 85.3% (n=110) were male at birth. The median age was 36 years [30-45]. Among the 129 PLWHIV, 34.1% (n=44) tested positive for serum cryptococcal antigen. In contrast, 65.9% (n=85) PLWHIV tested negative for serum cryptococcal antigen.

Overall, CSF CrAg was positive in 19.4% of patients (n=7); this included 20% (n=6) of those with a positive serum CrAg (SCrAg) and 16.7% (n=1) of those with a negative SCrAg. India ink staining was positive in 9.9% (n=9) of the patients, and cryptococcal cultures in CSF were positive in 20.0% (n=17), with no difference in the antigen-positive group, 27.8% (n=10) vs the antigen-negative group, 14.3% (n=7) (p=0.124).

Cryptococcal meningitis was diagnosed in 15.5% (n = 20) of patients, occurring more often in the serum antigen-positive group (27.3%, n = 12) compared to the serum antigen-negative group (9.4%, n = 8; p = 0.008).

Universal SCrAg screening in hospitalized PLWHIV increased lumbar puncture rates and cryptococcal meningitis diagnoses. However, despite early treatment, our results did not show a difference in hospital mortality.

All Authors: No reported disclosures