title: Case report: false negative serum cryptococcal latex agglutination test in a patient with disseminated cryptococcal disease.
abstract: A case of false-negative serum latex agglutination cryptococcal antigen (CRAG) test in a 45-year-old HIV-positive male with Cryptococcus-positive culture is described. The patient was presented to a hospital in Botswana, with breathlessness and a diffuse papular rash. His CD4 count was 25 cells/μL. Despite the suspicion for disseminated cryptococcal disease, an initial serum CRAG latex test was negative. Results of subsequent Indian ink staining, culture of cerebrospinal fluid and skin scrapings, and serum lateral flow immunoassay (LFA) were all positive for Cryptococcus neoformans. There are several possible explanations for the false-negative CRAG latex test. Given the positive LFA result, we speculate that disease may have been caused by Cryptococcus gattii, which is estimated to be responsible for between 15% and 30% of all cryptococcal diseases in Botswana. Reduced sensitivity of CRAG latex assays for detecting C gattii may lead to underdiagnosis of cryptococcal infection.
authors.affiliation: University of Pennsylvania, Pennsylvania, PA, USA.
authors.forename: Nazlee
authors.initials: N
authors.lastname: Navabi
authors.affiliation: Princess Marina Hospital, Gaborone, Botswana.
authors.forename: Milton
authors.initials: M
authors.lastname: Montebatsi
authors.affiliation: University of Pennsylvania, Pennsylvania, PA, USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Scott
authors.affiliation: University of Pennsylvania, Pennsylvania, PA, USA.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Gluckman
authors.affiliation: University of Pennsylvania, Pennsylvania, PA, USA Botswana UPenn Partnership, Gaborone, Botswana michael.j.a.reid@gmail.com.
authors.forename: Michael J A
authors.initials: MJ
authors.lastname: Reid
mesh_terms: D000946:Antigens, Fungal / Q000097:blood; D018791:CD4 Lymphocyte Count; D003453:Cryptococcosis / Q000097:blood* / Q000175:diagnosis* / Q000209:etiology; D005189:False Positive Reactions; D015658:HIV Infections / Q000150:complications*; D006801:Humans; D007841:Latex Fixation Tests; D008297:Male; D008875:Middle Aged
chemical_list: D000946:Antigens, Fungal
keywords: Cryptococcus neoformans; HIV; latex agglutination; serotype bias