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HelpTest Code LAB2052 Q Fever IgM and IgG, Titer, Serum
Additional Codes
QFP
Useful For
Diagnosis of Coxiella burnetii, the causative agent of Q fever
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumOrdering 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 |
On-campus collections: Tube to 99 or deliver to University Extension Hospital Room EH318
Off-campus collections: Centrifuge and aliquot within 2 hours. Specimen to be stored/transported Refrigerated.
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.
Day(s) Performed
Monday through Saturday
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 |
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.
Method Description
An indirect immunofluorescence test is used for the measurement of IgM and IgG antibodies to Coxiella burnetii. Specific antibodies present in the serum of the patient react with rickettsial cells that have been previously fixed on a glass microscope slide. Fluorescein-labeled antihuman IgG or IgM conjugate is used to stain specific antibody bound to the substrate cells. The slides are examined with a fluorescence microscope for characteristic, apple-green fluorescence of the infected cell.(Edligner B. Immunofluorescence serology. A tool for prognosis of Q fever. Diagn Microbiol Infect Dis. 1985;3[4]:343-351; package inserts: Q fever IFA IgG. Focus Diagnostics, Inc; 12/2022; Q fever IFA IgM. Focus Diagnostics, Inc; 12/2022)
Report Available
Same day/1 to 3 daysSpecimen Retention Time
14 daysReject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
Method Name
Only orderable as a reflex. For more information see QFEVR / Q Fever Antibody Screen with Titer Reflex, Serum.
Indirect Immunofluorescence
Testing Algorithm
For more information see Infective Endocarditis: Diagnostic Testing for Identification of Microbiological Etiology.