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Test ID: EHRC Ehrlichia chaffeensis (HME) Antibody, IgG, Serum

Reporting Name

Ehrlichia Chaffeensis (HME) Ab, IgG

Useful For

An adjunct in the diagnosis of ehrlichiosis

 

Seroepidemiological surveys of the prevalence of the infection in certain populations

Clinical Information

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.

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.

Testing Algorithm

See Acute Tick-Borne Disease Testing Algorithm in Special Instructions.

Analytic Time

Same day/1 day

Day(s) and Time(s) Performed

Monday through Friday; 9 a.m.

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

Method Name

Immunofluorescence Assay (IFA)

Specimen Type

Serum


Specimen Required


Container/Tube: 

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL


Specimen Minimum Volume

0.15 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.

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 U.S. Food and Drug Administration.

CPT Code Information

86666

LOINC Code Information

Test ID Test Order Name Order LOINC Value
EHRC Ehrlichia Chaffeensis (HME) Ab, IgG 47405-6

 

Result ID Test Result Name Result LOINC Value
81478 Ehrlichia Chaffeensis (HME) Ab, IgG 47405-6

Forms

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

Mayo Clinic Laboratories | Neurology Catalog Additional Information:

mml-CNS-Infections, mml-Pediatric