Histoplasma capsulatum Antibody Screen, Serum
Evaluating persons with symptoms of respiratory disease, as an aid in the presumptive laboratory diagnosis of Histoplasma infection
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
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.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Negative: Indicates antibodies to Histoplasma were not detected. The absence of antibodies is presumptive evidence that the patient was not infected with Histoplasma. However, the specimen may have been drawn before antibodies were detectable, or the patient may be immunosuppressed. If infection is suspected, another specimen should be drawn 7 to 14 days later and tested.
Equivocal: Specimens with equivocal EIA results will be tested by complement fixation and immunodiffusion.
Positive: The presence of antibodies is presumptive evidence that the patient was previously or is currently infected with (or exposed to) Histoplasma. These specimens will be tested by complement fixation and immunodiffusion for confirmation.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
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. Specimens obtained very early in the infection may not have detectable antibodies.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
Kaufman L, Kovacs JA, Reiss E: Clinical immunomycology. In Manual of Clinical Laboratory Immunology. 5th edition. Washington DC, ASP Press, 1997