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.
* This volume does not allow for repeat testing
Allow blood to clot for 30 minutes after collection
Centrifuge and separate serum off of cells into a transport tube
Specimen >14 days old
Any specimen types other than serum or CSF
Ship on dry ice to arrive Monday‐Friday using a next day delivery service.
Frozen ice packs may be substituted if sample is shipped the day of collection.
* This volume does not allow for repeat testing
Specimen >14 days old
Any specimen types other than serum or CSF
Ship on dry ice to arrive Monday‐Friday using a next day delivery service.
Frozen ice packs may be substituted if sample is shipped the day of collection.
Changing January 3, 2025
Negative: <10.0 EU
Intermediate: 10.0 – 19.9 EU
Positive: ≥20.0 EU
January 3, 2025 New Reference Range
Negative: <10.0 EU
Intermediate: 10.0 – 19.9 EU
Positive: ≥20.0 EU
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.
Limitations:
12% cross reactivity with Blastomycosis
24% cross reactivity with Coccidioidomycosis
1 to 2 days
00913334
86635 x 2