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# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Anaplasma phagocytophilum (Human Granulocytic Ehrlichiosis) Antibody, Serum (ANAP)
Test Code: ANAPSO
Synonyms/Keywords
​Ehrlichiosis Serology
Human Granulocytic Anaplasmosis (HGA)
Human Granulocytic Ehrlichiosis (HGE)
Anaplasma phagocytophilum
Useful For
As an adjunct in the diagnosis of human granulocytic ehrlichiosis
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
​No ​Serum ​Serum Separator Tube (SST) ​Red Top Tube (RTT) ​0.5 mL ​0.5 mL ​0.15 mL
Specimen Stability Information
Specimen Type Temperature Time
​Serum ​ ​Refrigerate (preferred) ​14 days
​Frozen ​14 days
Rejection Criteria
Gross Hemolysis
​Gross Lipemia
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Medical Laboratories ​Monday through Friday ​1-3 days ​Immunofluorescence Assay (IFA)
Reference Lab
Test Information

Human granulocyte ehrlichiosis (HGE) is a zoonotic infection caused by a rickettsia-like agent. The infection is acquired by contact with Ixodes ticks carrying the HGE agent. The deer mouse is the animal reservoir and, overall, the epidemiology is very much like that of Lyme disease and babesiosis. HGE is most prevalent in the upper Midwest and in other areas of the United States that are endemic for Lyme disease. Since its first description in 1994, there have been approximately 50 cases of HGE described in the upper Midwest.

The cellular target in HGE cases is the neutrophil. The organisms exist in membrane-lined vacuoles within the cytoplasm of infected host cells. Ehrlichial inclusions, called morulae, contain variable numbers of organisms. Single organisms, wrapped in vacuolar membranes have also been observed in the cytoplasm. Ehrlichia species occur in small electron-dense and large electron-lucent forms, but a clear life cycle has not been elucidated.

Diagnosis of human ehrlichiosis has been difficult because the patient's clinical course is often mild and nonspecific, including fever, myalgias, arthralgias, and nausea. This is easily confused with other illnesses such as influenza or other tickborne zoonoses such as Lyme disease, babesiosis, and Rocky Mountain spotted fever. Clues to the diagnosis of ehrlichiosis in a patient with an acute febrile illness after tick exposure include laboratory findings of leukopenia or thrombocytopenia and elevated serum aminotransferase levels. However, these findings may also be present in patients with Lyme disease or babesiosis.

Reference Range Information
Performing Location Reference Range
​Mayo Medical Laboratories ​<1.64
Interpretation
A positive result of an immunofluorescence assay (IFA) test (titer > or =1:64) suggests current or previous infection with human granulocytic ehrlichiosis. 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, PCR testing is available to aid in the diagnosis of these cases.
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​86666 ​1
Synonyms/Keywords
​Ehrlichiosis Serology
Human Granulocytic Anaplasmosis (HGA)
Human Granulocytic Ehrlichiosis (HGE)
Anaplasma phagocytophilum
Ordering Applications
Ordering Application Description
​Centricity ​Anaplasma Ab IgG, S
​Cerner ​Anaplasma Ab IgG, S
​COM ​Anaplasma Ab IgG, S
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
​No ​Serum ​Serum Separator Tube (SST) ​Red Top Tube (RTT) ​0.5 mL ​0.5 mL ​0.15 mL
Specimen Stability Information
Specimen Type Temperature Time
​Serum ​ ​Refrigerate (preferred) ​14 days
​Frozen ​14 days
Rejection Criteria
Gross Hemolysis
​Gross Lipemia
Useful For
As an adjunct in the diagnosis of human granulocytic ehrlichiosis
Test Information

Human granulocyte ehrlichiosis (HGE) is a zoonotic infection caused by a rickettsia-like agent. The infection is acquired by contact with Ixodes ticks carrying the HGE agent. The deer mouse is the animal reservoir and, overall, the epidemiology is very much like that of Lyme disease and babesiosis. HGE is most prevalent in the upper Midwest and in other areas of the United States that are endemic for Lyme disease. Since its first description in 1994, there have been approximately 50 cases of HGE described in the upper Midwest.

The cellular target in HGE cases is the neutrophil. The organisms exist in membrane-lined vacuoles within the cytoplasm of infected host cells. Ehrlichial inclusions, called morulae, contain variable numbers of organisms. Single organisms, wrapped in vacuolar membranes have also been observed in the cytoplasm. Ehrlichia species occur in small electron-dense and large electron-lucent forms, but a clear life cycle has not been elucidated.

Diagnosis of human ehrlichiosis has been difficult because the patient's clinical course is often mild and nonspecific, including fever, myalgias, arthralgias, and nausea. This is easily confused with other illnesses such as influenza or other tickborne zoonoses such as Lyme disease, babesiosis, and Rocky Mountain spotted fever. Clues to the diagnosis of ehrlichiosis in a patient with an acute febrile illness after tick exposure include laboratory findings of leukopenia or thrombocytopenia and elevated serum aminotransferase levels. However, these findings may also be present in patients with Lyme disease or babesiosis.

Reference Range Information
Performing Location Reference Range
​Mayo Medical Laboratories ​<1.64
Interpretation
A positive result of an immunofluorescence assay (IFA) test (titer > or =1:64) suggests current or previous infection with human granulocytic ehrlichiosis. 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, PCR testing is available to aid in the diagnosis of these cases.
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Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Medical Laboratories ​Monday through Friday ​1-3 days ​Immunofluorescence Assay (IFA)
Reference Lab
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​86666 ​1
For most current information refer to the Marshfield Laboratory online reference manual.