Histoplasma Antibody, IgG / IgM

Overview

  • EPIC Code:
  • IMO4110
  • Soft Test Code:
  • HISAB
  • Send Out Test Code:
  • 326
Alternate Names
  • Histoplasma AB IgG IgM EIA
  • Histoplasma Antibody, IgG & IgM
  • MVista® HISTOPLASMA ANTIBODY IgG IgM EIA
Clinical Significance

IgM and IgG antibodies to Histoplasma antigen usually appear during the first month of infection. The IgM antibody response in acute pulmonary histoplasmosis is detectable during the acute phase (roughly 3 weeks) and is shown to decline during the convalescent stage (at about 6 weeks); whereas, IgG levels remained relatively constant at 6 weeks. Follow-up testing may be considered 2-4 weeks after initial testing to determine if antibody levels are increasing, especially in patients with low positive (10 EU – 20 EU) or intermediate results. Increase in IgG antibody or decrease in IgM concentration would suggest recent infection. Antibodies may persist for several years in patients with chronic pulmonary complications or progressive extrapulmonary (disseminated) histoplasmosis. Antibodies may be falsely-negative in some progressive or chronic cases, especially in immunocompromised patients. Antibodies may also be detected in healthy subjects who are asymptomatic as a result of sub-clinical infection within the last 18-36 months.


Specimen Collection & Preparation

Specimen Requirements

1.0 mL Serum from a Red Top Tube in a Plastic Vial


Transport And Storage

14 days Ambient
14 days Refrigerated
14 days Frozen


Collection Instructions

Collect serum specimens in serum separator or red top tube. Allow blood to clot for 30 minutes, then centrifuge. Pipette serum into a plastic screw cap vial.


Minimum Volume

0.5 mL Serum


Neonatal Volume

Clinical Interpretation

Reference Range:

Negative


Test Comments:

Negative: <8.0 EU

Intermediate: 8.0 EU-9.9 EU

Positive: 10.0 EU-80.0 EU


Methodology:
  • Semi-Quantitative Indirect Enzyme Immunoassay (EIA)
Clinical Significance

IgM and IgG antibodies to Histoplasma antigen usually appear during the first month of infection. The IgM antibody response in acute pulmonary histoplasmosis is detectable during the acute phase (roughly 3 weeks) and is shown to decline during the convalescent stage (at about 6 weeks); whereas, IgG levels remained relatively constant at 6 weeks. Follow-up testing may be considered 2-4 weeks after initial testing to determine if antibody levels are increasing, especially in patients with low positive (10 EU – 20 EU) or intermediate results. Increase in IgG antibody or decrease in IgM concentration would suggest recent infection. Antibodies may persist for several years in patients with chronic pulmonary complications or progressive extrapulmonary (disseminated) histoplasmosis. Antibodies may be falsely-negative in some progressive or chronic cases, especially in immunocompromised patients. Antibodies may also be detected in healthy subjects who are asymptomatic as a result of sub-clinical infection within the last 18-36 months.


Documentation

Limitation

  • 12% cross reactivity with Blastomycosis
  • 24% cross reactivity with Coccidioidomycosis

  • Production Schedule

    Sites Performed
    • MiraVista
    Days Performed
    Monday
    Wednesday
    Thursday
    Friday
    Departments
    • Sendouts - Clinical
    Turn Around Time

    1 day


    Coding & Compliance

    CDM

    00918390


    CPT Coding

    86698 x 2