Aiding in the diagnosis of Histoplasma meningitis using spinal fluid specimens
For more information see Meningitis/Encephalitis Panel Algorithm
Complement Fixation (CF)/Immunodiffusion (ID)
HICSF
Histoplasma meningitis
For more information see Meningitis/Encephalitis Panel Algorithm
CSF
This test should be ordered if patient is seropositive for Histoplasma antibodies in serum.
Container/Tube: Sterile vial
Specimen Volume: 1 mL
Collection Instructions: Submit specimen from collection vial 1.
0.8 mL
Gross hemolysis | OK |
Gross lipemia | OK |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
CSF | Refrigerated (preferred) | 14 days | |
Frozen | 14 days |
Aiding in the diagnosis of Histoplasma meningitis using spinal fluid specimens
For more information see Meningitis/Encephalitis Panel Algorithm
Histoplasma capsulatum is a dimorphic fungus endemic to the Midwestern United States, particularly along the Mississippi River and Ohio River valleys. Infection occurs following inhalation of fungal microconidia, and subsequent clinical manifestations are largely dependent on the fungal burden at the time of exposure and the patient's underlying immune status. While the vast majority (>90%) of exposed individuals will remain asymptomatic, individuals seeking medical attention can present with a diverse set of symptoms ranging from a self-limited pulmonary illness to severe, disseminated disease. Individuals at risk for severe infection include those with impaired cellular immunity, who have undergone organ transplantation, who are HIV positive, or who have a hematologic malignancy.
The available laboratory methods for the diagnosis of H capsulatum infection include fungal culture, molecular techniques, serologic testing, and antigen detection. While culture remains the gold standard diagnostic test and is highly specific, prolonged incubation is often required, and sensitivity decreases (9%-34%) in cases of acute or localized disease. Similarly, molecular methods offer high specificity but decreased sensitivity. Serologic testing likewise offers high specificity; however, results may be falsely negative in immunosuppressed patients or those who present with acute disease. Also, antibodies may persist for years following disease resolution, thereby limiting the clinical specificity.
Anti-Yeast Antibody by Complement Fixation
Negative (positive results reported as titer)
Antibody by Immunodiffusion
Negative (positive results reported as band present)
Any positive serologic result in spinal fluid is significant.
Simultaneous appearance of the H and M precipitin bands indicates active histoplasmosis.
The M band alone indicates active or chronic disease or a recent skin test for histoplasmosis.
Antibody levels may be low in spinal fluid in cases of Histoplasma meningitis.
Histoplasmin skin tests yield specific antibodies in titratable quantity and may cause difficulties in interpretation.
Cross-reacting antibodies with coccidioidomycosis or blastomycosis may cause false-positive results for Histoplasmosis.
1. Kaufman L, Kovacs JA, Reiss E. Clinical immunomycology. In: Rose NR, de Macario ED, Folds JD, Lane HC, Nakamura RM, eds. Manual of Clinical Laboratory Immunology. ASM Press; 1997
2. Deepe GS. Histoplasma capsulatum Histoplasmosis. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Elsevier; 2020:3162-3176
Both immunodiffusion and compliment fixation (CF) tests are used to detect antibodies to Histoplasma capsulatum. For immunodiffusion, the antigen is a culture filtrate, histoplasmin. H and M precipitin bands are identified. For the CF test, the antigens are histoplasmin and a yeast form of Histoplasma capsulatum; the latter is more sensitive.(Roberts GD. Fungi. In: Washington II, JA eds. Laboratory Procedures in Clinical Microbiology. 2nd ed. Springer-Verlag; 1985; Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Elsevier; 2020)
Monday through Friday
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
86698 x2
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
HICSF | Histoplasma Ab CompFix/ImmDiff, CSF | 91684-1 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
621217 | Histoplasma Yeast CompFix, CSF | 27209-6 |
621218 | Histoplasma Immunodiffusion, CSF | 91682-5 |
Change Type | Effective Date |
---|---|
New Test | 2024-06-04 |