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Rtyphiiggmsmtser

Published: August 9, 2026Updated: August 14, 2026

A blood test that detects IgG antibodies against Rickettsia typhi, the bacteria that causes murine typhus, to help determine if you have been infected.

Quick summary

{"Detects IgG antibodies indicating past or recent Rickettsia typhi infection","Sample is collected from a blood draw (serum)","Positive result suggests current or previous infection requiring treatment","Murine typhus is typically transmitted by fleas from rodents","Antibodies usually appear 7-14 days after infection"}

Medically reviewed by WellAlly Editorial TeamLast reviewed August 14, 2026Editorial policy

Key facts at a glance

LOINC
111048-5
Short code
RICKTYPI
Synonyms
R typhi IgG Msmt Ser
Category
cardiac
Sample
serum
Container
Serum Separator Tube (SST) or plain red top tube
Units
N/A
Ref low
0
Ref high
1
Fasting
false
Population
adult
Sex
all
Age range
0–120 years
Method
Immunofluorescence Assay (IFA)
CPT
86617
SNOMED
406565006
Specimen volume
1.0-2.0 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
40
TAT
48–120 hours
Order
routine

What is this test?

The Rickettsia typhi IgG Antibody test is a blood test that looks for IgG antibodies in your serum. IgG antibodies are proteins your immune system produces to fight Rickettsia typhi, the bacteria that causes murine typhus (also known as endemic typhus). This test helps your healthcare provider determine if you have been infected with this bacterium.

Why might I need this test?

Your doctor may order this test if you have symptoms of murine typhus, such as fever, severe headache, rash, muscle pain, or chills. This is especially important if you have recently been exposed to areas with rodents or fleas, or if your symptoms started after a flea bite. The test helps confirm whether your symptoms are due to a Rickettsia typhi infection.

How is the test performed?

A healthcare professional will draw a small blood sample from a vein in your arm. This blood sample will be sent to a laboratory where technicians will analyze your serum for the presence of IgG antibodies against Rickrellsia typhi. The results are typically available within a few days.

What do the results mean?

A positive result means IgG antibodies were detected in your blood, indicating that you have been infected with Rickettsia typhi at some point. A negative result means no antibodies were detected, which could mean you have not been infected, or that the infection is very recent and antibodies have not yet developed. Your doctor will interpret these results together with your symptoms and medical history.

Reference range

Negative: <1:64; Equivocal: 1:64; Positive: ≥1:128 (titers may vary by laboratory; paired acute/convalescent sera showing 4-fold rise in titer is diagnostic for acute infection)N/A

Specimen: serum

No special preparation required. Fasting is not necessary. Inform the laboratory of any recent infections, travel history, or exposure to endemic areas.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

How is murine typhus transmitted?
Murine typhus is transmitted through the bite of infected fleas. These fleas typically come from rats, but can also be found on other animals like cats and opossums. The disease is more common in warm climates and coastal areas.
What are the symptoms of murine typhus?
Symptoms usually begin 7-14 days after infection and include high fever, severe headache, rash (typically on the trunk of the body), muscle pain, nausea, and vomiting. Some patients may also experience a cough or abdominal pain.
Is treatment necessary if I test positive?
Yes, if you test positive for Rickettsia typhi infection, treatment with antibiotics (usually doxycycline) is recommended. Early treatment helps prevent complications and speeds up recovery. Most patients improve within 48-72 hours of starting antibiotics.
Can I get murine typhus more than once?
Once you have been infected and recovered, you typically develop immunity that protects against future infections. However, as with many infections, it is still important to take precautions to avoid flea bites.
  1. 1
    CDC - Murine Typhus (Endemic Typhus)Source
  2. 2
    Mayo Clinic Laboratories - Rickettsia typhi IgGSource

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.

Medical Disclaimer

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