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Test ID EHRCP Ehrlichia Antibody Panel, Serum

Reporting Name

Ehrlichia Ab Panel

Useful For

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

 

Seroepidemiological surveys of the prevalence of the infection in certain populations

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

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Specimen Required


Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL


Specimen Minimum Volume

0.25 mL

Specimen Stability Information

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

Reference Values

ANAPLASMA PHAGOCYTOPHILUM

<1:64

Reference values apply to all ages.

 

EHRLICHIA CHAFFEENSIS

<1:64

Reference values apply to all ages.

Day(s) and Time(s) Performed

Monday through Friday; 9 a.m.

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 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

Testing Algorithm

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

Clinical Information

Anaplasma phagocytophilum:

A 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:

E 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.

Cautions

Serology for IgG may be negative during the acute phase of infection (<7 days postsymptom onset), during which time detection using targeted nucleic acid amplification testing (eg, PCR) is recommended.

 

Detectable IgG-class antibodies typically appear within 7 to 10 days postsymptom 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, E ewingii) may not be detected by this assay.

Clinical Reference

CDC. Tick-borne diseases of the United States: A Reference Manual for Health Care Providers. Fourth Edition, 2017

Analytic Time

Same day/1 day

Reject Due To

Hemolysis

Mild OK; Gross reject

Lipemia

Mild OK; Gross reject

Icterus

Mild OK; Gross reject

Other

Heat-inactivated specimen

NY State Approved

Yes

Method Name

Immunofluorescence Assay (IFA)

Forms

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