Rtyphiandsfiggigmspecimp
This blood test detects antibodies against Rickettsia typhi and spotted fever group bacteria to diagnose rickettsial infections.
{"Detects IgM (recent infection) and IgG (past infection) antibodies","Helps diagnose typhus and spotted fever diseases","Sample collected via blood draw from a vein","Results help guide appropriate antibiotic treatment","May require repeat testing to confirm diagnosis"}
Key facts at a glance
- LOINC
- 66718-8
- Short code
- RT-SFG-IG
- Synonyms
- R typhi and SF IgG+IgM Spec-Imp
- Category
- cardiac
- Sample
- serum
- Container
- Serum separator tube (SST) or red top plain tube
- Units
- N/A
- Ref low
- 2
- Ref high
- 4
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Immunofluorescence assay (IFA) or Enzyme-linked immunosorbent assay (ELISA)
- CPT
- 86757
- SNOMED
- 122442006
- Specimen volume
- 1-2 mL of serum
- Stability
- Room temperature: 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 50
- Lipemia max
- 300
- Icterus max
- 20
- TAT
- 48–96 hours
- Order
- routine
What is this test?
The Rickettsia typhi and Rickettsia spotted fever group IgG and IgM test is a blood test that detects specific antibodies produced by your immune system in response to Rickettsia bacteria. These bacteria are transmitted through insect bites (typically from fleas, mites, or ticks) and can cause diseases such as murine typhus and spotted fever.
What do IgG and IgM mean?
IgM antibodies are the first antibodies your body produces when fighting a new infection. They typically appear within 1-2 weeks after infection and indicate a recent or current infection. IgG antibodies develop later and remain in your body for longer, providing immunity against future infections. Testing for both helps determine if you have an active infection or had one in the past.
How is the test performed?
A healthcare professional will draw a small blood sample from a vein in your arm. The sample is then sent to a laboratory where it is analyzed for the presence of IgG and IgM antibodies against Rickettsia typhi and spotted fever group bacteria. No special preparation is typically required before the test.
What diseases does this test detect?
This test helps diagnose two main types of rickettsial diseases: (1) Murine typhus (Rickettsia typhi), typically transmitted by fleas and causing symptoms like fever, headache, and rash; (2) Spotted fever group infections, including Rocky Mountain spotted fever and other tick-borne rickettsial diseases, which can cause severe illness if not treated promptly.
Reference range
Negative: <1:64 (IgG), <1:64 (IgM); Equivocal: 1:64 to 1:128 (IgG), 1:64 to 1:128 (IgM); Positive: >=1:128 (IgG), >=1:128 (IgM). A fourfold rise in titer between acute and convalescent sera collected 2-4 weeks apart is diagnostic.N/A
No special preparation required. Inform laboratory of recent infections, antibiotic therapy, or known immunocompromised state.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
Do I need to fast before this test?
How long does it take to get results?
What do positive results mean?
Do I need repeat testing?
Is this test dangerous?
Sources
- 1
- 2
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 14, 2026. · Read our editorial policy