Rickettsial Disease Panel
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
R. Typhi IgG/IgM
Reference Range: Not Detected
Q Fever IgG/IgM Phase I/II Screens
Reference Range: Negative
Q Fever Antibody testing includes differentiation of antibodies to Phase I and Phase II antigenic variants. Coxiella burnetii, which causes Q Fever, undergoes transitions between Phase I and Phase II states. These phases are serologically distinguishable and useful in the serodiagnosis of acute and chronic disease.
In some cases, the ratio of titer of phase II to phase I may indicate the stage of the disease. A ratio of greater than 1 may indicate the acute stage; greater than or equal to 1, granulomatous hepatitis; and less than 1, the chronic stage or endocarditis.
As with other infectious diseases, IgM antibodies are the first to appear. Usually they are detectable for a few weeks or, at the most, for a few months. IgG antibodies appear somewhat later but can persist for years, even for life.
Although single phase II IgG titers of 1:256 or greater are considered evidence of acute C. burnetii disease, the best criterion for a dependable diagnosis is still the demonstration of a fourfold or higher increase in antibody titer between the acute and convalescent serum samples.
Test Performed By: Focus Diagnostics, Inc.
5785 Corporate Avenue
Cypress, CA 90630-4750