Histoplasma and Blastomyces Antigen, Serum (Sendout)

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General Information

Lab Name
Histoplasma and Blastomyces Antigen, Serum (Sendout)
Lab Code
RHIBAG
Epic Ordering
Histoplasma and Blastomyces Antigen, Serum (Sendout)
External Test Id
HIBAG
Description

Useful For:

  • Diagnosing Histoplasma capsulatum or Blastomyces dermatitidis infection without differentiation between the organisms
  • Monitoring antigen levels following initiation of antifungal treatment

Test Highlights:

  • This test detects Histoplasma and Blastomyces antigen in serum, without differentiation between the 2 fungal pathogens.
  • It aids in the diagnosis of histoplasmosis or blastomycosis alongside other routine methods, including culture, molecular testing, and serology.
  • This test can be used to monitor response to antifungal therapy.
References
Synonyms
Blastomyces dermatitidis antigen, HIBAG, Histoplasma Antigen, Histoplasma capsulatum Antigen, Histoplasma Polysaccharide Antigen, RHISTO
Components

Interpretation

Method

Enzyme Immunoassay (EIA)

Reference Range
See individual components
Ref. Range Notes

Reference Values:

Histoplasma/Blastomyces Antigen Result: Not Detected
Histoplasma/Blastomyces Antigen Value: Not Detected

Interpretation:

Not detected: No antigen from Histoplasma or Blastomyces detected. False-negative results may occur depending on extent of disease or site of infection. Repeat testing on a new specimen if clinically indicated.

Detected, <1.5 ng/mL: Antigen from Histoplasma or Blastomyces (unable to differentiate) was detected, below the limit of quantification (<1.5 ng/mL). Result should be correlated with clinical presentation, exposure history, and other diagnostic procedures, such as culture, serology, histopathology, and radiographic findings to aid in the differentiation between histoplasmosis or blastomycosis.

Detected, 1.5-25.0 ng/mL: Antigen from Histoplasma or Blastomyces (unable to differentiate) detected. Result should be correlated with clinical presentation, exposure history, and other diagnostic procedures, such as culture, serology, histopathology, and radiographic findings, to aid in the differentiation between histoplasmosis and blastomycosis.

Detected, >25.0 ng/mL: Antigen from Histoplasma or Blastomyces (unable to differentiate) detected, above the limit of quantification (>25.0 ng/mL). Result should be correlated with clinical presentation, exposure history, and other diagnostic procedures, such as culture, serology, histopathology, and radiographic findings, to aid in the differentiation between histoplasmosis or blastomycosis.

Interferences and Limitations

Cautions:

Due to significant cross-reactivity between galactomannan antigens from Blastomyces and Histoplasma, this assay does not differentiate between these 2 dimorphic fungal agents. To differentiate, consider fungal culture, molecular testing, or serology testing.

Positive results should be correlated with other clinical and laboratory findings (e.g., culture, serology).

Low-level positive antigen levels may persist following resolution of infection and completion of appropriate treatment regimen.

Sensitivity of this assay to detect antigen from species other than Blastomyces dermatitidis or Histoplasma capsulatum is unknown.

False positive results may occur less frequently with other dimorphic agents (e.g., Coccidioides).

References
Guidelines

Ordering & Collection

Specimen Type
Blood
Collection

5 mL in GOLD SST or RED TOP tube

Handling Instructions

Outside Laboratories: Centrifuge sample and transfer serum to a separate plastic vial. Refrigerate serum while awaiting shipment. Transport with a cold pack.

Stability: Refrigerated (preferred): 28 days; Frozen: 28 days; Ambient: 72 hours.

Reject Due To: Gross hemolysis, gross lipemia, gross icterus, or heat-inactivated specimen.

Quantity
requested: 1.5 mL serum
minimum: 1.2 mL serum

Processing

Processing

Centrifuge sample and transfer serum to a separate plastic vial. Refrigerate serum.

Sendouts:

  • Order Mayo Test: HIBAG
  • Interfaced: Yes [Interface: 601; Worksheet: MARF]

Stability: Refrigerated (preferred): 28 days; Frozen: 28 days; Ambient: 72 hours.

Reject Due To: Gross hemolysis, gross lipemia, gross icterus, or heat-inactivated specimen.

Performance

LIS Dept Code
Sendouts Mayo Lab (RF) (MARF)
Performing Location(s)
Sendout Mayo Clinic Laboratories (Superior Drive)
800-533-1710

3050 Superior Drive NW
Rochester, MN 55901
Frequency
Performed: Monday through Saturday. Reported: 1-3 days from sample receipt at Mayo Clinic Labs.
Available STAT?
No

Billing & Coding

CPT codes
87449
LOINC
19145-2