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For hours, walk-ins and appointments.Ehrlichia chaffeensis (HME) Antibody, IgG and IgM, IFA
CPT:
86666(x2)
Synonyms
- Ehrlichia
- HME
- Tickborne
Expected Turnaround Time
1 - 4 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Related Documents
Specimen Requirements
Specimen
Serum
Volume
0.4 mL
Minimum Volume
0.2 mL
Container
Gel-barrier tube, red-top tube or serum transfer tube
Collection
If tube other than a gel-barrier tube is used, transfer separated serum to a labeled plastic transport tube. Do not freeze gel-barrier tube; pour off serum first.
Storage Instructions
Room temperature
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 14 days |
Refrigerated | 14 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x4 |
Causes for Rejection
Hemolysis; lipemia; gross bacterial contamination; frozen gel-barrier tube
Test Details
Use
This test is used for detection and semiquantitation of serum IgG and IgM antibodies to Ehrlichia chaffeensis to aid in the diagnosis of human monocytic ehrlichiosis (HME).
Confirmation of diagnosis is based on laboratory testing, but antibiotic therapy should not be delayed in patients with a suggestive clinical presentation. The diagnosis of acute ehrlichiosis cannot be confirmed solely by the presence of antibodies in a serum sample collected at a single timepoint. DNA PCR can be used to diagnose acute infection. Demonstration of a 4-fold rise in IgG-specific antibody titers by IFA in paired samples (acute and convalescent) confirms infection with E. chaffeensis. IgM antibodies are less specific than IgG antibodies and are more likely to generate false positive results. IgM results alone should not be used for laboratory diagnosis. Antibody titers are frequently negative during the first 7-10 days of illness.
Limitations
The diagnosis of acute ehrlichiosis cannot be confirmed solely by the presence of Ehrlichia antibody in a serum sample collected at a single time point.
Methodology
Indirect fluorescent antibody (IFA)
Reference Interval
• IgG negative: <1:64
• IgM negative: <1:20
References
Centers for Disease Control and Prevention (CDC). Tickborne Diseases of the United States: A reference manual for healthcare providers. Sixth edition. 2022. CDC website: https://www.cdc.gov/ticks/tickbornediseases/index.html. Accessed May 2023.
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 164680 | Ehrlichia chaffeensis Ab | 164681 | E. chaffeensis IgG | 47405-6 | ||
| 164680 | Ehrlichia chaffeensis Ab | 164704 | E. chaffeensis IgM | 48850-2 | ||
| 164680 | Ehrlichia chaffeensis Ab | 164118 | Result Comment: | N/A |
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