An adjunct in the diagnosis of infection with Anaplasma phagocytophilum or Ehrlichia chaffeensis
Seroepidemiological surveys of the prevalence of the infection in certain populations
Test Id | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
ANAP | Anaplasma phagocytophilum Ab, IgG,S | Yes | Yes |
EHRC | Ehrlichia Chaffeensis (HME) Ab, IgG | Yes | Yes |
For more information see Acute Tick-Borne Disease Testing Algorithm.
Immunofluorescence Assay (IFA)
Tick Borne Diseases
E. chaffeensis
A. phagocytophilum
HME (Human Monocytotropic Ehrlichiosis)
Human Granulocytic Anaplasmosis (HGA)
For more information see Acute Tick-Borne Disease Testing Algorithm.
Serum
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.
If not ordering electronically, complete, print, and send Infectious Disease Serology Test Request (T916) with the specimen.
See Specimen Required
Gross hemolysis | Reject |
Gross lipemia | Reject |
Gross icterus | Reject |
Heat-inactivated specimen | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Refrigerated (preferred) | 14 days | |
Frozen | 14 days |
An adjunct in the diagnosis of infection with Anaplasma phagocytophilum or Ehrlichia chaffeensis
Seroepidemiological surveys of the prevalence of the infection in certain populations
For more information see Acute Tick-Borne Disease Testing Algorithm.
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.
Ehrlichia chaffeensis is an intracellular rickettsia-like bacterium that preferentially infects monocytes and is sequestered in parasitophorous vacuoles referred to as morulae. Infections with E chaffeensis are also referred to as human monocytotropic ehrlichiosis (HME). E chaffeensis is transmitted by Amblyomma species ticks, which are found throughout the Southeastern and South-Central United States.
Many cases of HME are subclinical or mild, however, the infection can be severe and life-threatening, particularly in immunosuppressed individuals. Reported mortality rates range from 2% to 3%. Fever, fatigue, malaise, headache, and other "flu-like" symptoms occur most commonly. Leukopenia, thrombocytopenia, and elevated hepatic transaminases are frequent laboratory findings.
ANAPLASMA PHAGOCYTOPHILUM
<1:64
Reference values apply to all ages.
EHRLICHIA CHAFFEENSIS
<1:64
Reference values apply to all ages.
A positive immunofluorescence assay result (titer > or =1:64) suggests current or previous infection. In general, the higher the titer, the more likely the patient has an active infection. Four-fold rises in titer also indicate active infection.
Previous episodes of ehrlichiosis may produce a positive serology result although antibody levels decline significantly during the year following infection.
Serology results for IgG may be negative during the acute phase of infection (<7 days post-symptom onset), during which time detection using targeted nucleic acid amplification testing (eg, polymerase chain reaction) is recommended.
Detectable IgG-class antibodies typically appear within 7 to 10 days post-symptom onset.
IgG-class antibodies may remain detectable for months to years following prior infection. Therefore, a single time point-positive titer needs to be interpreted alongside other findings to differentiate recent versus past infection.
Other members of the Ehrlichia genus (eg, Ehrlichia ewingii) may not be detected by this assay.
Centers for Disease Control and Prevention (CDC), Division of Vector-Borne Diseases: Tickborne Diseases of the United States: A Reference Manual for Healthcare Providers. 6th ed. US Department of Health and Human Services; 2022. Accessed September 5, 2024. Available at www.cdc.gov/ticks/tickbornediseases/TickborneDiseases-P.pdf
The patient's serum is diluted and is placed in microscopic slide wells that have been coated with Anaplasma phagocytophilum-infected cells or Ehrlichia chaffeensis-infected cells. After incubation, the slides are washed and a fluorescein-isothiocyanate conjugate is added to each well. The slides are then read using a fluorescence microscope and significant fluorescent staining of intracellular organisms constitutes a positive reaction.(Dumler JS, Asanovich KM, Bakken JS, Richter P, Kimsey R, Madigan JE. Serologic cross-reactions among Ehrlichia equi, Ehrlichia phagocytophila, and human granulocytic Ehrlichia. J Clin Microbiol. 1995;33[5]:1098-1103; Pancholi P, Kolbert CP, Mitchell PD, et al. Ixodes dammini as a potential vector of human granulocytic ehrlichiosis. J Infect Dis. 1995;172[4]:1007-1012; Dawson JE, Fishbein DB, Eng TR, Redus MA, Green NR. Diagnosis of human ehrlichiosis with the indirect fluorescent antibody test: kinetics and specificity. J Infect Dis. 1990;162[1]:91-95; package insert: Ehrlichia chaffeensis IFA IgG. DiaSorin Molecular; 08/2016)
Monday through Friday
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.
86666 x 2
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
EHRCP | Ehrlichia Ab Panel | 77165-9 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
81157 | Anaplasma phagocytophilum Ab, IgG,S | 23877-4 |
81478 | Ehrlichia Chaffeensis (HME) Ab, IgG | 47405-6 |