Lab Test

Coxiella burnetti Antibodies, IgG

Q-Fever Antibody IgG

Test Codes

Mayo: QFP, EPIC: LAB5993, Beaker: XCOX

Department

Send Outs

Instructions

Acute and convalescent specimens must be labeled as such; parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of the acute samples. Please mark sample plainly as "acute" or "convalescent."

Specimen Collection Criteria

Collect (preferred specimen): One Gold-top SST tube.
Also acceptable: One plain Red-top tube. 

Physician Office/Draw Specimen Preparation

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells within two hours of collection. Transfer serum to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Preparation for Courier Transport

Transport: 0.5 mL serum, refrigerated (2-8°C or 36-46°F). (Minimum: 0.3 mL)

Rejection Criteria

  • Hemolyzed specimens.
  • Severely lipemic specimens.
  • Specimens not collected and processed as indicated.

In-Lab Processing

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells within two hours of collection. Transfer serum to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Transport: 0.5 mL serum, refrigerated (2-8°C or 36-46°F). (Minimum: 0.3 mL)

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): unacceptable
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 7 days

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Mayo Clinic Laboratories in Rochester, MN.

Performed

Monday – Friday.
Results available in 2-4 days.

Reference Range

By report.

Test Methodology

Indirect Immunofluorescence.

Interpretation

By report.

Clinical Utility

This assay aids in the diagnosis of Q-fever. Antibodies to Phase II predominate in acute disease and those to Phase I in chronic disease.

Clinical Disease

The clinical features of Q-fever include a fever (near 40°C) that peaks in 2-4 days and then gradually declines for 1-2 weeks. This initial fever may be accompanied by malaise, anorexia, myalgias, weakness, and intense headache. Q-fever may also manifest as pneumonitis or bronchitis. Endocarditis is an uncommon complication following a protracted latent phase.

Epidemiology

Coxiella burnetii, the organism which causes Q-fever, is an obligate intracellular parasite (family Rickettsiaceae) with worldwide distribution. It is unique within this group of organisms in that it undergoes a phase transition, similar to the smooth-rough lipopolysaccharide transitions seen in the enteric gram-negative bacteria. Virulent isolates are of the phase I type, while serial passage in eggs or tissue culture is required for selection of the avirulent phase II transition. These phases are seologically distinguishable and quite useful in the seodiagnosis of both acute and chronic C. burnetii infections.

Incubation Period

Q-fever has an incubation period of approximately 2-3 weeks.

Transmission

Dairy cattle, sheep, and cats are important reservoirs of C. burnetii. Recent evidence has also implicated rodents, as well as the cats that feed on them.  Infection in these animals in enzootic and nearly always inapparent. Transmission of Q-fever to humans is via inhalation of contaminated dust particles and aerosols, and via handling and ingestion of infected meat and milk.

CPT Codes

86638 x4

Contacts

Last Updated

11/12/2020

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