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:

-OR-

1.0 mL Serum from a Red Top Tube in a Plastic Vial
Minimum Volume:
0.5 mL Serum*

* This volume does not allow for repeat testing

Processing Instructions:

Allow blood to clot for 30 minutes, then centrifuge.

Pipette serum into a plastic screw cap vial.


Rejection Criteria:

>14 days old

Any specimen types other than serum or CSF


Transport and Storage:
  • Ambient (18-24°C): 14 Days
  • Refrigerated (2-8°C): 14 Days
  • Frozen (-20° C or colder): 14 Days

    Transport 

-OR-

1.0 mL CSF in a Sterile Plastic Vial
Minimum Volume:
0.5 mL CSF *

* This volume does not allow for repeat testing

Rejection Criteria:

>14 days old

Any specimen types other than serum or CSF


Transport and Storage:
  • Ambient (18-24°C): 14 Days
  • Refrigerated (2-8°C): 14 Days
  • Frozen (-20° C or colder): 14 Days

    Transport 

Clinical Interpretation

Reference Range:

Negative


Test Comments:

Interpretavive 

  • Negative: <10.0 EU
  • Intermediate: 10.0 EU-19.9 EU
  • Positive: 20.0 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
Thursday
Departments
  • Sendouts - Clinical
Turn Around Time

1 to 2 days


Coding & Compliance

CDM

00918390


CPT Coding

86698 x 2