ARUP's Laboratory Test Directory

Ehrlichia chaffeensis Antibody, IgG by IFA : 0051004

Mnemonic: E CH G

Methodology: Semi-Quantitative Indirect Fluorescent Antibody
Performed: Tue, Fri
Reported: 1-5 days
Specimen Required: Collect: Serum separator tube.

Specimen Preparation: Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.05 mL) Parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of the acute specimens. Mark specimens plainly as acute or convalescent.

Storage/Transport Temperature: Refrigerated.

Unacceptable Conditions: Contaminated, hemolyzed, or severely lipemic specimens.

Stability (collection to initiation of testing): After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)

Reference Interval:
< 1:64 Negative-No significant level of Ehrlichia chaffeensis IgG antibody detected.
1:64-1:128 Equivocal-Questionable presence of Ehrlichia chaffeensis IgG antibody detected. Repeat testing in 10-14 days may be helpful.
≥1:256 Positive-Presence of IgG antibody to Ehrlichia chaffeensis detected, suggestive of current or past infection.
Interpretive Data: Seroconversion between acute and convalescent sera is considered strong evidence of recent infection. The best evidence for infection is a significant change (fourfold difference in titer) on two appropriately timed specimens, where both tests are done in the same laboratory at the same time.

See Compliance Statement B: www.aruplab.com/CS
Note: Human ehrlichiosis is a tick-borne disease caused by rickettsial-like agents. Two forms, human monocytic ehrlichiosis (HME) and human granulocytic ehrlichiosis (HGE), have been described. HME is often referred to as "spotless" or rashless Rocky Mountain spotted fever, and has been reported in various regions of the United States. The causative agent of HME has been identified as Ehrlichia chaffeensis. Infected individuals produce specific antibodies to E. chaffeensis, which can be detected by an immunofluorescent antibody (IFA) test.
CPT Code(s): 86666
Cross References: Human Monocytic Ehrlichiosis (HME) (Ehrlichia chaffeensis Antibody, IgG by IFA)