Lab Dept:


Test Name:

Histoplasma CAPSULATUM Antibody

General Information

Lab Order Codes:

HAB – Complement Fixation


Histoplasma Antibody, Serum; Histoplasma Ab; Histoplasma Complement Fixation; Immunodiffusion for Fungi

CPT Codes:

86698 X3 - Antibody; histoplasma

Test Includes:

Histoplasma Antibody by Complement Fixation


Test Indications:

Useful as an aid in the diagnosis of respiratory disease when Histoplasma infection is suspected.

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.

Lab Testing Sections:

Serology - Sendouts

Referred to:

Mayo Medical Laboratories (Mayo Test: SHSTO)

Phone Numbers:

MIN Lab: 612-813-6280

STP Lab: 651-220-6550

Test Availability:

Daily, 24 hours

Turnaround Time:

1 – 2 days, test is set up Sunday - Friday

Special Instructions:



Specimen Type:



Red top tube

Draw Volume:

6 mL (Minimum: 1.5 mL) blood

Processed Volume:

2 mL (Minimum: 0.5 mL) serum


Routine venipuncture


Special Processing:

Lab Staff: Centrifuge specimen and remove serum aliquot into a screw-capped round bottom plastic tube. Store and send serum refrigerated. Forward promptly.

Patient Preparation:


Sample Rejection:

Specimen collected in incorrect container; specimen other than serum; gross hemolysis; mislabeled or unlabeled specimens


Reference Range:

Complement Fixation/Immunodiffusion test:

Mycelial by complement fixation: negative (positives reported as titer)

Yeast by complement fixation: negative (positives reported as titer)

Antibody by immunodiffusion: negative (positives reported as band present)

Complement fixation (CF) titers ≥1:32 indicate active disease. A rising CF titer is associated with progressive infection.

Positive immunodiffusion test results supplement CF test result.

Patients infected with H. 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.

Critical Values:



The use of this assay has not been established for screening the general population or for monitoring therapy.

The performance of this assay has not been established for ruling out diseases with similar symptoms eg, diseases caused by Mycobacterium tuberculosis, Coccidioides immitis, Aspergillus fumigatus, Blastomyces dermatitidis, Streptococcus pneumoniae, Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella pneumophila or other pathogens.

The performance of this assay has not been established for matrices other than serum.

All results from this and other serologies must be correlated with clinical history, epidemiological data, and other data available to the attending physician in evaluating the patient.

The prevalence of infection will affect the assay's predictive value.

The test can be positive with persons that are not currently infected with histoplasma. Antibodies may be present because of a past infection.

The test can be negative with persons that are currently infected with Histoplasma. Samples obtained very early in the infection may not have detectable antibodies.


Complement Fixation (CF)/Immunodiffusion


Mayo Medical Laboratories (July 2013)


1/28/16: CPT update, screening test no longer offered.