Anaplasma phagocytophilum (HGA) Antibodies, IgG and IgM

Also known as: HGE G/M

Clinical Use

Use

This test is used for the detection of IgG and IgM antibodies against Anaplasma phagocytophilum, useful for diagnosing acute or convalescent phases of infection, especially when PCR testing is not feasible, like when the infection is outside the acute phase's two-week window. Anaplasma phagocytophilum, the causative agent of human granulocytic anaplasmosis (HGA), is transmitted by tick bites. Detecting antibodies can help confirm a diagnosis in patients with clinical and epidemiological suspicion of tick-borne disease.

Special Instructions

Not provided.

Limitations

This test has not been cleared or approved by the FDA and is performed in a CLIA-certified laboratory for clinical purposes. A positive IgM result alone might not confirm the disease; testing of both acute and convalescent specimens is recommended. Co-infection with Lyme Disease and/or Babesiosis should be considered. The sensitivity and specificity of the test can be influenced by timing of specimen collection and the patient's immune response.

Test Details

New York Approved

Methodology

Immunoassay (IHC)

Biomarkers

A. phagocytophilum Antibody, IgG

Protein

Titer

Expression • Ordinal Score (e.g., TPS, CPS, H-score)

A. phagocytophilum Antibody, IgM

Protein

Titer

Expression • Ordinal Score (e.g., TPS, CPS, H-score)

LOINC Codes

Result Codes

23877-4 - A phagocytoph IgG Titr Ser IF
23878-2 - A phagocytoph IgM Titr Ser IF

Result Turnaround Time

1-5 days

Specimen

Serum

Volume

1 mL

Minimum Volume

0.4 mL

Container

ARUP standard transport tube

Collection Instructions

Separate serum from cells ASAP or within 2 hours of collection. Parallel testing is preferred, and convalescent specimens must be received within 30 days from receipt of acute specimens. Mark specimens plainly as 'acute' or 'convalescent.'