Ctfviggtitrser
A blood test that detects IgG antibodies against Colorado tick fever virus to determine past infection or immunity.
{"Detects IgG antibodies indicating previous Colorado tick fever infection","Helps confirm past exposure to the virus transmitted by ticks","Not typically used for acute diagnosis - IgM test is preferred for active infection","Positive result suggests immunity to the virus","Sample is collected from blood (serum)"}
Key facts at a glance
- LOINC
- 16121-6
- Short code
- CTF IgG
- Synonyms
- CTFV IgG Titr Ser
- Category
- cardiac
- Sample
- serum
- Container
- Serum separator tube (SST) or red top tube
- Units
- N/A
- Ref low
- 8
- Ref high
- 16
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Immunofluorescence Assay (IFA) or Enzyme-Linked Immunosorbent Assay (ELISA)
- CPT
- 86635
- SNOMED
- 371949004
- Specimen volume
- 1-2 mL serum minimum
- Stability
- Room temperature: 8 hours; Refrigerated (2-8°C): 72 hours; Frozen (-20°C or below): several weeks
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 72–168 hours
- Order
- routine
What is this test?
The Colorado Tick Fever Virus IgG Antibody Test is a blood test that detects IgG antibodies in your serum. IgG antibodies are produced by your immune system after exposure to the Colorado tick fever virus, which is transmitted through the bite of an infected tick (Dermacentor andersoni). This test helps determine if you have had a previous infection with the virus.
Why is this test performed?
This test is typically ordered to confirm whether a person has been previously infected with Colorado tick fever, especially in areas where the disease is common (primarily the western United States). It may also be used in epidemiological studies to understand the prevalence of the infection in a population.
What do the results mean?
A positive IgG result indicates that you have been infected with Colorado tick fever virus at some point in the past and likely have developed immunity. A negative result means no previous infection has been detected, though this could also mean the infection was very recent and antibodies haven't developed yet, or the infection occurred so long ago that antibody levels have declined.
How is the test performed?
A healthcare professional will draw a small blood sample from a vein in your arm. The blood is then sent to a laboratory where it is analyzed to detect the presence of IgG antibodies against Colorado tick fever virus. No special preparation is typically required before this test.
Reference range
Negative: <1:8 titer; Equivocal: 1:8-1:16 titer; Positive: >1:16 titer (may vary by laboratory)N/A
No special preparation required. Inform laboratory of recent tick exposure or travel to endemic areas.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
Is this test used to diagnose an active infection?
Do I need to fast before this test?
How long does it take to get results?
Is the test safe?
What should I do if my result is positive?
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 16, 2026. · Read our editorial policy