Anaplasma phagocytophilum Antibodies (IgG, IgM)
Also known as: HGE, Human Granulocytic Ehrlichiosis (HGE)
Use
Anaplasma phagocytophilum is a tick‑borne agent that causes an acute febrile illness that often resembles Rocky Mountain spotted fever. Detection of IgG and IgM antibodies provides supportive laboratory evidence of infection, particularly when comparing acute and convalescent specimens, recognizing that serologic testing may be negative in early illness and IgM is less reliable as indication of recent infection than IgG.
Special Instructions
Not provided.
Limitations
Serologic testing by IFA (indirect fluorescent antibody) may be negative in the first week of illness; IgM is less reliable for diagnosing recent infection; antibodies may remain elevated for months or years after infection; cross‑reactivity with related organisms (e.g., Ehrlichia) may occur. Single acute antibody results cannot confirm infection; seroconversion (four‑fold rise in IgG titer) is preferred. IgG titer ≥1:64 (or ≥1:128 supportive), IgM ≥1:20 (per reference) thresholds apply.
Methodology
Immunoassay (IHC)
Biomarkers
Result Turnaround Time
1-2 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL (preferred)
Minimum Volume
0.2 mL
Container
SST (gold top) tube; alternate red top plain tube accepted
Collection Instructions
Collect serum via venipuncture; separate serum from cells as soon as possible or within 2 hours
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days |
| Refrigerated | 14 days |
| Frozen | 30 days |