Table 3.

Studies Analyzing Association Between Blood Cryptococcal Antigen Titer and Concurrent Cryptococcal Meningitis and/or Death

Country	Year	Study design	Association between blood CrAg titer and concurrent CM	Notes	Ref
Association between blood CrAg titer and concurrent CM
Democratic Republic of Congo (DRC)	1989	Cross-sectional study of 44 newly diagnosed HIV infected adults performing baseline blood and CSF CrAg titers (LA).	Higher titers associated with increasing risk of concurrent cryptococcal meningitis (PPV 92% for titer >128).	Concurrent CM present in 29/44 (66%) CrAg-positive patients. Symptoms unknown.	[21]
Cambodia	2007	Cross-sectional study screening patients with CD4 ≤200 cells/µL and performing LPs in all CrAg-positive patients (n=53).	Median titer (LA) higher in those with than those without concurrent CM (2048 vs. 16, p<0.0001).	Concurrent CM present in 41/53 (78%). Most symptomatic.	[19]
Thailand	2010	Retrospective study performed blood CrAg titers (LA) on 12 asymptomatic CrAg-positive patients who had baseline LPs.	Higher CrAg titers in those with CM than those without (128-1024 vs. 8-128).	Concurrent subclinical CM in 3/12 (25%).	[13]
South Africa	2016	Prospective study implementing CrAg screen and treat. Blood CrAg titers (LFA) on 10 patients who had a baseline LP.	Higher titers associated with concurrent CM No CM in patients with titers of <160.	Concurrent CM present in 4/10 (40%). Symptoms unknown.	[10]
Ethiopia	2017	Cross-sectional screening of all HIV- infected adults admitted to hospital. Serum CrAg titers (LFA) and LP for all CrAg positive patients.	Serum titers of ≥160 in 12/16 (75%) patients with concurrent CM. Two patients without concurrent CM had serum titers of 40.	Concurrent CM in 16/18 (89%). All symptomatic.	[22]

Abbreviations: CM, cryptococcal meningitis; CrAg, cryptococcal antigen; CSF, cerebrospinal fluid; HIV, human immunodeficiency virus; LA, latex agglutination; LFA, lateral flow assay; LP, lumbar puncture; PPV, positive predictive value.