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Test ID: QFP Q Fever IgM and IgG, Titer, Serum

Reporting Name

Q Fever IgM/IgG, Titer, S

Useful For

Diagnosis of Coxiella burnetii, the causative agent of Q fever

Clinical Information

Q fever, a rickettsial infection caused by Coxiella burnetii, has been recognized as a widely distributed zoonosis with the potential for causing both sporadic and epidemic disease. The resistance of C burnetii to heat, chemical agents, and desiccation allows the agent to survive for extended periods outside the host.

 

C burnetii is spread by the inhalation of infected material, largely from dried sheep and goat reproductive material; the organism is also shed in feces, milk, nasal discharge, placental tissue, and amniotic fluid from ruminant animals.

 

The clinical spectrum of disease ranges from unapparent to fatal. Respiratory manifestations usually predominate; endocarditis and hepatitis can be complications.

 

During the course of the infection, the outer membrane of the organism undergoes changes in its lipopolysaccharide structure, called phase variation. Differences in the host antibody response between phase I and phase II antigens can help classify infections as either acute or chronic:

-In acute Q fever, the phase II antibody is generally higher than the phase I titer, often by 4-fold, even in early specimens. Although a rise in phase I as well as phase II titers may occur in later specimens, the phase II titer remains higher.

-In chronic Q fever, the reverse situation is generally seen. Serum specimens collected late in the illness from chronic Q fever patients demonstrate significantly higher phase I titers, sometimes much greater than 4-fold.

-In the case of chronic granulomatous hepatitis, IgG and IgM titers to phase I and phase II antigens are quite elevated, with phase II titers generally equal to or greater than phase I titers.

-Titers seen in Q fever endocarditis are similar in magnitude, although the phase I titers are quite often higher than the phase II titers.

Interpretation

A negative result argues against Coxiella burnetii infection. If early acute Q fever infection is suspected, collect a second specimen 2 to 3 weeks later and retest.

 

A negative result following a reactive C burnetii enzyme immunoassay screen suggests a falsely reactive screen. In cases of suspected acute C burnetii infection, repeat testing in 2 to 3 weeks is recommended.

 

Phase I antibody titers greater than or equal to phase II antibody titers are consistent with chronic infection or convalescent phase Q fever.

 

Phase II antibody titers greater than or equal to phase I antibody titers are consistent with acute/active infection.

 

In Q fever sera, it is common to see IgG titers of 1:128 or greater to both phase I and phase II antibody titers. IgG class antibody titers appear very early in the disease, reaching maximum phase II titers by week 8 and persisting at elevated titers for longer than a year. Phase I titers follow the same pattern, although at much lower levels, and may not be initially detected until convalescence.

 

In Q fever sera, it is common to see IgM titers of 1:64 or greater.

 

IgM class antibody titers appear very early in the disease, reaching maximum phase II titers by week 3 and declining to very low levels by week 14. Phase I titers follow the same pattern, although at much lower levels, and may not be initially detected until convalescence.

Report Available

Same day/1 to 3 days

Day(s) Performed

Monday through Saturday

Clinical Reference

1. Hartzell JD, Marrie TJ, Raoult D. Coxiella burnetii (Q fever). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Elsevier; 2020:2360-2367

2. Anderson A, Bijlmer H, Fournier PE, et al. Diagnosis and management of Q fever--United States, 2013: recommendations from CDC and the Q Fever Working Group [published correction appears in MMWR Recomm Rep. 2013 Sep 6;62(35):730]. MMWR Recomm Rep. 2013;62(RR-03):1-30

Method Name

Only orderable as a reflex. For more information see QFEVR / Q Fever Antibody Screen with Titer Reflex, Serum.

 

Indirect Immunofluorescence

Specimen Type

Serum


Ordering Guidance


 



Specimen Required


Only orderable as a reflex. For more information see QFEVR / Q Fever Antibody Screen with Titer Reflex, Serum.

 

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Specimen Minimum Volume

0.25 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 7 days
  Frozen  7 days

Reference Values

Only orderable as a reflex. For more information see QFEVR / Q Fever Antibody Screen with Titer Reflex, Serum.

 

Q fever phase I antibody, IgG

<1:16

 

Q fever phase II antibody, IgG

<1:16

 

Q fever phase I antibody, IgM

<1:16

 

Q fever phase II antibody, IgM

<1:16

 

Reference values apply to all ages.

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

86638 x 4

LOINC Code Information

Test ID Test Order Name Order LOINC Value
QFP Q Fever IgM/IgG, Titer, S 77175-8

 

Result ID Test Result Name Result LOINC Value
80965 Q Fever Phase I Ab, IgG 34716-1
24011 Q Fever Phase II Ab, IgG In Process
81115 Q Fever Phase I Ab, IgM 9710-5
24009 Q Fever Phase II Ab, IgM 9711-3
24010 Interpretation 69048-7
Mayo Clinic Laboratories | Neurology Catalog Additional Information:

mml-CNS-Infections, mml-Pediatric