FDG PET/CT Skull and Thigh for Tumor Localization, Without Contrast
A PET/CT scan that uses radioactive FDG to help locate tumors in the skull and thigh. It is performed without iodinated IV contrast.
["This scan shows areas of abnormal FDG uptake that may help identify and locate a tumor, but findings require clinical interpretation."]
Key facts at a glance
- LOINC
- 82808-7
- Short code
- PT+CT Skull-thigh Tum loc W FDG+WO contr
- Synonyms
- PT+CT Skull-thigh Tum loc W FDG+WO contr
- Category
- liver
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0.8
- Ref high
- 1.2
- Critical range
- — – 5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- pt-ct
- CPT
- 85610
- SNOMED
- 396252006
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What is this test?
This is a positron emission tomography/computed tomography (PET/CT) scan used to help locate tumors. A radioactive tracer called fluorodeoxyglucose (FDG) is given before the scan, and PET imaging measures areas of increased tracer uptake while CT provides detailed anatomy.
Why might I need this test?
It may be ordered to evaluate a known or suspected tumor, identify the tissue taking up the most FDG, or help guide a biopsy, surgery, or other treatment. It may also be used to assess how a tumor responds to treatment.
How is the test performed?
After receiving FDG through a vein, you lie on a scanning table while the PET/CT machine collects images of the specified areas. The examination may take a longer time than a standard CT scan. Because the study is performed without iodinated IV contrast, a contrast-related reaction is less likely.
How do I prepare for the test?
The imaging center will provide specific instructions, which may include fasting for several hours and limiting strenuous exercise. Tell the care team about diabetes, medications, pregnancy or breastfeeding, allergies, and recent surgery, because any of these may affect preparation or image quality.
Reference range
INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A
Inform your healthcare provider if you are taking blood thinners. No special preparation required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Increased FDG uptake may occur where a tumor is present, but it is not specific for cancer. Inflammation, infection, healing tissue, and some other conditions can also appear active on PET imaging. Low or absent uptake does not completely exclude a tumor, so results must be interpreted with the scan images, medical history, and other tests.
Short name
FDG PET/CT for Tumor Localization
Frequently asked questions
Does this test use contrast?
Can an abnormal PET/CT result confirm cancer?
Why might my blood sugar affect the result?
Sources
- 1
- 2Lab Tests OnlineSource
- 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