Volume 20, Number 1—January 2014
Multisite Validation of Cryptococcal Antigen Lateral Flow Assay and Quantification by Laser Thermal Contrast
|Cohort||CSF LFA titer||Serum CRAG LFA titer||Serum CRAG latex titer||Urine LFA result||Classification||Patient outcome|
|2006–2009||2||NA||NA||NA||LFA false positive||Unknown|
||LFA false positive
|2010–2012||2||512||1:8||–||Cryptococcal meningitis||Began ART; CSF culture-positive result; meningitis developed 6 weeks later|
|±||2,048||2,048||–||Cryptococcal meningitis||Died after hospital discharge|
|±||32||–||+||Cryptococcal meningitis||Died in hospital|
|250||4||–||+||Cryptococcal meningitis||Began ART; minimum CD4 cell count 130 cells/μL|
|8||8||128||–||Cryptococcal meningitis||Died after hospital discharge|
|±/16†||4,096||2,048||+||Cryptococcal meningitis||Given fluconazole, 800 mg/d; seizure; died; cryptococcoma mass identified postmortem|
*CSF, cerebrospinal fluid; CRAG, cryptococcal antigen; LFA, lateral flow immunochromatographic assay; –, negative’ NA, not available; ART, antiretroviral therapy; ±, discordant readings by 2 independent readers; +, positive. All test results for CSF culture, India ink microscopy, and CSF CRAG latex were negative.
†Fresh specimen was CRAG latex and LFA negative. CRAG LFA titer of 16 on cryopreserved specimen. Repeat CSF testing results 2 weeks later for neurologic deterioration were positive and remained CRAG latex negative. Thermal contrast showed that all LFA strips had positive results with readings above background.