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Test Code EHRLICHHG Anaplasma phagocytophilum (Human Granulocytic Ehrlichiosis) Antibody, Serum

Additional Codes

Mayo Test ID
ANAP

Reporting Name

Anaplasma phagocytophilum Ab, IgG,S

Useful For

As an adjunct in the diagnosis of human granulocytic ehrlichiosis (anaplasmosis)

 

Seroepidemiological surveys of the prevalence of the infection in certain populations

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Specimen Minimum Volume

0.4 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 14 days
  Frozen  14 days

Reference Values

<1:64

Reference values apply to all ages.

Day(s) Performed

Monday through Friday

Test Classification

This test was developed using an analyte specific reagent. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

86666

LOINC Code Information

Test ID Test Order Name Order LOINC Value
ANAP Anaplasma phagocytophilum Ab, IgG,S 23877-4

 

Result ID Test Result Name Result LOINC Value
81157 Anaplasma phagocytophilum Ab, IgG,S 23877-4

Testing Algorithm

For more information see Acute Tick-Borne Disease Testing Algorithm.

Clinical Information

Anaplasma phagocytophilum is an intracellular rickettsia-like bacterium that preferentially infects granulocytes and forms inclusion bodies, referred to as morulae. A phagocytophilum is transmitted by Ixodes species ticks, which also transmit Borrelia burgdorferi and Babesia species. Infection with A phagocytophilum is also referred to as human granulocytic anaplasmosis (HGA) or human granulocytic ehrlichiosis, and symptoms in otherwise healthy individuals are often mild and nonspecific, including fever, myalgia, arthralgia, and nausea. Clues to the diagnosis of anaplasmosis in a patient with an acute febrile illness after tick exposure include laboratory findings of leukopenia or thrombocytopenia and elevated liver enzymes. HGA is most prevalent in the upper Midwest and in other areas of the United States that are endemic for Lyme disease.

Interpretation

A positive result of an immunofluorescence assay (IFA) test (titer ≥1:64) suggests current or previous infection with human granulocytic ehrlichiosis (anaplasmosis). In general, the higher the titer, the more likely it is that the patient has an active infection.

 

Seroconversion may also be demonstrated by a significant increase in IFA titers.

 

During the acute phase of the infection, serologic tests are often nonreactive, polymerase chain reaction (PCR) testing is available to aid in the diagnosis of these cases (see EPCRB / Ehrlichia/Anaplasma, Molecular Detection, PCR, Blood).

Cautions

Previous episodes of human granulocytic ehrlichiosis (anaplasmosis) may produce a positive serologic result.

 

In rare instances, clinical evidence of infection may also be derived by direct microscopic examination of Giemsa- or Diff-Quik-stained peripheral blood buffy coat smears, which may reveal clusters of round, dark-purple stained, small dots (morulae) in the cytoplasm of polymorphonuclear cells. However, this is a very insensitive method.

 

Performance characteristics have not been established for hemolyzed or lipemic specimens.

Report Available

1 to 3 days

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus Reject
Heat-inactivated specimen Reject

Method Name

Immunofluorescence Assay (IFA)

Forms

If not ordering electronically, complete, print, and send Infectious Disease Serology Test Request (T916) with the specimen.