Aiding in the diagnosis of active histoplasmosis using serum specimens
For information see Meningitis/Encephalitis Panel Algorithm.
Complement Fixation (CF)/Immunodiffusion (ID)
fungal serology
histo
Histoplasma capsulatum
Histoplasma Complement Fixation
Histoplasmosis
Immunodiffusion Serology for Fungi
For information see Meningitis/Encephalitis Panel Algorithm.
Serum
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions: Centrifuge and aliquot serum into plastic vial.
If not ordering electronically, complete, print, and send Infectious Disease Serology Test Request (T916) with the specimen.
See Specimen Required
Gross hemolysis | Reject |
Gross lipemia | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Refrigerated (preferred) | 14 days | |
Frozen | 14 days |
Aiding in the diagnosis of active histoplasmosis using serum specimens
For information see Meningitis/Encephalitis Panel Algorithm.
Histoplasma capsulatum is a soil saprophyte that grows well in soil enriched with bird droppings. The usual disease is self-limited, asymptomatic, and affects the lungs. Chronic cavitary pulmonary disease, disseminated disease, and meningitis may occur and can be fatal, especially in young children and in immunosuppressed patients.
MYCELIAL BY COMPLEMENT FIXATION (CF):
Negative (positives reported as titer)
YEAST BY CF:
Negative (positives reported as titer)
ANTIBODY BY IMMUNODIFFUSION:
Negative (positives reported as band present)
Complement fixation (CF) titer results of 1:32 or higher indicate active disease. A rising CF titer is associated with progressive infection.
Positive immunodiffusion test results supplement findings of the CF test. The simultaneous appearance of both H and M precipitin bands indicates active histoplasmosis. The M precipitin band alone indicates early or chronic disease or a recent histoplasmosis skin test.
Patients infected with Histoplasma capsulatum demonstrate a serum antibody with a rising titer within 6 weeks of infection. A rising titer is associated with progressive infection. Specific antibody persists for a few weeks to a year, regardless of clinical improvement.
Recent histoplasmosis skin tests must be avoided because the test causes a misleading rise in complement fixation titer, as well as an M precipitin band, in approximately 17% of patients having previous exposure to Histoplasma capsulatum.
Cross-reacting antibodies sometimes present interpretive problems in patients having blastomycosis or coccidioidomycosis.
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 and Laboratory Immunology. 5th ed. ASP 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 complement fixation (CF) tests are used to detect antibodies to Histoplasma capsulatum. For immunodiffusion, the antigen used is a culture filtrate. Histoplasmin H and M precipitins can be identified by the assay. For the CF test, antigens are histoplasmin and a yeast form antigen of Histoplasma capsulatum; the latter is more sensitive.(Roberts GD: Fungi. In: Washington II JA, ed. 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 x 3
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
SHSTO | Histoplasma Ab, S | 90227-0 |
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.
|
---|---|---|
15121 | Histoplasma Mycelial | 20573-2 |
15122 | Histoplasma Yeast | 20574-0 |
15123 | Histoplasma Immunodiffusion | 90232-0 |