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Epic Code LAB1230705 Ehrlichia Antibody Panel, Serum

Additional Codes

Mayo Code: EHRCP

Interface Code: 1230705

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

An adjunct in the diagnosis of infection with Anaplasma phagocytophilum or Ehrlichia chaffeensis

 

Seroepidemiological surveys of the prevalence of the infection in certain populations

Specimen Type

Serum


Specimen Required


Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL


Laboratory Test Directory Note:

COLLECTION NOTE: Volumes listed are in serum or plasma, draw approximately 2 1/2 times the requested volume in whole blood.

Specimen Minimum Volume

See Specimen Required

Forms

If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.

Specimen Stability Information

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

Reject Due To

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

Cautions

Serology 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: PCR) 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.

Clinical Information

Anaplasma phagocytophilum, an intracellular rickettsia-like bacterium, 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) 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.

Method Name

Immunofluorescence Assay (IFA)

Report Available

Same day/1 to 3 days

Reporting Name

Ehrlichia Ab Panel

Reference Values

ANAPLASMA PHAGOCYTOPHILUM

<1:64

Reference values apply to all ages.

 

EHRLICHIA CHAFFEENSIS

<1:64

Reference values apply to all ages.

Interpretation

A positive immunofluorescence assay (titer ≥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 although antibody levels decline significantly during the year following infection.

Method Description

The patient's serum is diluted and is placed in microscopic slide wells that have been coated with Anaplasma phagocytophilum-infected cells and/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 phagocytophilia, and human granulocytic ehrlichia. J Clin Microbiol. 1995 May;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 Oct;172(4):1007-1012; Dawson JE, Fishbein DB, Eng TR, et al: Diagnosis of human ehrlichiosis with the indirect fluorescent antibody test: kinetics and specificity. J Infect Dis. 1990 Jul;162(1):91-95; package insert: Ehrlichia chaffeensis IFA IgG. DiaSorin Molecular; 08/2016)

Day(s) Performed

Monday through Friday

Clinical Reference

Centers for Disease Control and Prevention (CDC), Division of Vector-Borne Diseases: Tickborne diseases of the United States: A Reference Manual for Health Care Providers. 4th ed. CDC; 2017

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 x 2

LOINC Code Information

Test ID Test Order Name Order LOINC Value
EHRCP Ehrlichia Ab Panel 77165-9

 

Result ID Test Result Name Result LOINC Value
81157 Anaplasma phagocytophilum Ab, IgG,S 23877-4
81478 Ehrlichia Chaffeensis (HME) Ab, IgG 47405-6

Profile Information

Test ID Reporting Name Available Separately Always Performed
ANAP Anaplasma phagocytophilum Ab, IgG,S Yes Yes
EHRC Ehrlichia Chaffeensis (HME) Ab, IgG Yes Yes