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Test ID: SHSTO Histoplasma Antibody, Serum

Reporting Name

Histoplasma Ab, S

Useful For

Aiding in the diagnosis of active histoplasmosis using serum specimens

Clinical Information

Histoplasma capsulatum is a soil saprophyte that grows well in soil enriched with bird droppings. The usual disease is self-limited, affects the lungs, and is asymptomatic. Chronic cavitary pulmonary disease, disseminated disease, and meningitis may occur and can be fatal, especially in young children and in immunosuppressed patients.


Complement fixation (CF) titers 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.

Testing Algorithm

See Meningitis/Encephalitis Panel Algorithm in Special Instructions.

Report Available

2 to 7 days

Day(s) Performed

Monday through Friday

Clinical Reference

1. Kaufman L, Kovacs JA, Reiss E: Clinical Immunomycology. In: 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

Method Name

Complement Fixation (CF)/Immunodiffusion

Specimen Type


Specimen Required


Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL

Specimen Minimum Volume

See Specimen Required.

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 14 days
  Frozen  14 days

Reference Values


Negative (positives reported as titer)



Negative (positives reported as titer)



Negative (positives reported as band present)

Test Classification

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.

CPT Code Information

86698 x 3

LOINC Code Information

Test ID Test Order Name Order LOINC Value
SHSTO Histoplasma Ab, S 90227-0


Result ID Test Result Name Result LOINC Value
15121 Histoplasma Mycelial 20573-2
15122 Histoplasma Yeast 20574-0
15123 Histoplasma Immunodiffusion 90232-0


If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.

Mayo Clinic Laboratories | Neurology Catalog Additional Information:

mml-CNS-Infections, mml-Pediatric