Cryptococcal Meningitis: Likelihood Ratios

Introduction: Cryptococcal meningitis is caused by Cryptococcus neoformans and typically causes extremely high intracerebral pressures. Note that the serum antigen test is sensitive for AIDS patients only.

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The likelihood ratios of findings for Cryptococcal Meningitis are listed below. See the left navigation bar to change the display.

Good Positive and Negative Likelihood Ratios

Cryptococcal Antigen in Serum
Duplicate

5.9

in AIDS patients!

Specificity is from the first reference, which gives a sensitivity of only 91%.

Study: J Med Assoc Thai. 1999;82(1):65-71. PMID 10087741

J Clin Microbiol. 2005 Nov;43(11):5828-9. PMID: 16272534

Cryptococcal Antigen in CSF

13.3

0.1

at least 93% sensitivity and specificity (depending on the kit), versus culture as gold standard

similar sensitivity numbers from different series, across host types (see second reference)

Study: J Clin Microbiol. 1994;32(7):1680-4. PMID 7929757

J Clin Microbiol. 2005 Nov;43(11):5828-9. PMID: 16272534

Poorly Diagnostic Findings

Finding	+LR	-LR	Comments, Study
Cryptococcal Antigen in Serum Duplicate	Sensitivity = 87%		non-HIV immunocompromised. No data for immunocompetent hosts. Study: J Clin Microbiol. 2005 Nov;43(11):5828-9. PMID: 16272534
India Ink stain of CSF	Sensitivity = 75%		in AIDS patients. sensitivity is 50% in non-AIDS patients Study: UpToDate, references PMID 3299095 and PMID 4811791
Non-contrast Head CT	Sensitivity = 17%		abnormal findings include cryptococcomas and hydrocephalus. these were more common in non-AIDS and especially immunocompetent hosts. Study: Clin Infect Dis. (2000) 31 (2): 499-508. http://cid.oxfordjournals.org/content/31/2/499.long