Bfragilisdnactbldposqnnaaprobe
A molecular test that detects Bacteroides fragilis bacteria DNA in blood samples using nucleic acid amplification technology.
This test identifies a specific gut bacteria (Bacteroides fragilis) in blood It uses DNA detection methods to confirm bacterial presence after a blood culture flags positive Results help doctors determine if a dangerous bloodstream infection is present The test is performed on blood from patients with suspected sepsis or bacteremia Rapid detection helps guide appropriate antibiotic treatment
Key facts at a glance
- LOINC
- 105774-4
- Short code
- BFRAGDNA
- Synonyms
- B fragilis DNA Ct Bld Pos Qn NAA+probe
- Category
- chemistry
- Sample
- whole-blood
- Container
- Sterile blood culture bottle (aerobic and anaerobic pairs); positive culture broth transferred to molecular testing tube
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- probe-amp-tar
- CPT
- 87153
- SNOMED
- 122450006
- Specimen volume
- 3-10 mL of blood per culture bottle (pediatric: 1-3 mL); positive broth aliquot per laboratory protocol
- Stability
- Blood culture bottles: room temperature, incubate within 2 hours of collection; positive broth: stable at 2-8°C for up to 24 hours prior to molecular testing
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 2–8 hours
- Order
- routine
What is this test and why might my healthcare provider have ordered it for me?
This test detects the DNA of Bacteroides fragilis bacteria in blood samples that have already shown signs of bacterial growth. Bacteroides fragilis is a type of bacteria that normally lives in your intestines but can cause serious infections if it enters your bloodstream. The test uses a technique called Nucleic Acid Amplification (NAA) with probe detection to identify the specific genetic material of this bacteria quickly and accurately.
Why is this test performed and what important information about my health can it reveal?
When a blood culture test shows bacterial growth, doctors need to know exactly what type of bacteria is present to provide the right treatment. This test specifically identifies Bacteroides fragilis, which is an anaerobic bacteria (grows without oxygen) that can cause severe bloodstream infections, abdominal infections, and sepsis. Knowing the exact cause helps your healthcare team choose the most effective antibiotics.
How is this test done, and will I need to do anything special to prepare before the sample is collected?
A healthcare professional will collect a blood sample from a vein in your arm. The sample is then sent to a laboratory where technicians use specialized equipment to detect Bacteroides fragilis DNA. The test is performed on blood that has already been identified as having bacterial growth from a previous culture. Results are typically available within 24-48 hours.
What do the results mean, and what could it indicate if my values are higher or lower than the normal range?
A positive result means Bacteroides fragilis bacteria DNA was detected in your blood, confirming a Bacteroides fragilis infection. This helps your doctor determine the cause of your illness and select appropriate treatment. A negative result means the test did not find evidence of this specific bacteria, though other types of bacteria could still be present. Your doctor will interpret these results along with your symptoms and other test findings.
Reference range
Cycle threshold (Ct) value reported; no bacterial DNA detected (Ct not applicable). Quantitative interpretation based on Ct values: lower Ct indicates higher bacterial load.N/A
No special patient preparation required. Specimen should be collected prior to initiation of antimicrobial therapy when possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Bacteroides fragilis is a common cause of anaerobic bloodstream infections, often originating from the gastrointestinal tract. These infections can lead to sepsis, a life-threatening condition where the body's response to infection causes organ damage. This test provides rapid and specific detection, enabling targeted antibiotic therapy rather than broad-spectrum treatment. It is particularly important because Bacteroides fragilis has developed resistance to some antibiotics, making precise identification crucial for effective treatment. Early detection and appropriate treatment significantly improve patient outcomes in cases of Bacteroides bacteremia.
Frequently asked questions
Is this test painful?
Do I need to fast before this test?
How long does it take to get results?
What happens if the test is positive?
Can this test detect other bacteria?
Sources
- 1Mayo Clinic - BacteremiaSource
- 2CDC - SepsisSource
- 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