Bactvsviraletiolindpnlserpl
A blood test that helps doctors determine whether an infection is caused by bacteria or viruses, guiding appropriate treatment decisions.
{"This test measures markers like procalcitonin and CRP to distinguish bacterial from viral infections","Results help doctors decide whether antibiotics are needed","A simple blood draw is required, usually from a vein in your arm","Results are typically available within a few hours to a day"}
Key facts at a glance
- LOINC
- 101542-9
- Short code
- BVPAN
- Synonyms
- Bact vs viral etiol ind pnl SerPl
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) for serum; lavender-top (EDTA) tube for whole blood CBC component
- Units
- N/A
- Ref low
- 0.1
- Ref high
- 0.5
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 1–120 years
- Method
- Multi-analyte immunoassay panel including procalcitonin (PCT), C-reactive protein (CRP), and complete blood count with differential white blood cell analysis
- CPT
- 84145 (procalcitonin) + 86140 (CRP) + 85025 (CBC with differential)
- SNOMED
- 39579001
- Specimen volume
- 5-10 mL whole blood (minimum 3 mL for serum + 3 mL EDTA)
- Stability
- Serum: 8 hours at room temperature, 48 hours at 2-8°C, 3 months at -20°C. EDTA whole blood: 4 hours at room temperature for CBC analysis, 24 hours at 2-8°C.
- Hemolysis max
- 100
- Lipemia max
- 300
- Icterus max
- 50
- TAT
- 2–8 hours
- Order
- routine
What is this test?
The Bacterial versus Viral Etiology Indicator Panel is a blood test that measures specific substances in your blood to help determine whether your infection is caused by bacteria or a virus. This is important because bacterial infections typically require antibiotics, while viral infections do not. The test usually measures markers such as procalcitonin (PCT), C-reactive protein (CRP), and sometimes other indicators like white blood cell count.
How is the test performed?
A healthcare professional will draw a small blood sample from a vein in your arm using a needle. The area will be cleaned with alcohol before the draw. You may feel a brief pinch or sting. The sample is then sent to a laboratory for analysis. Fasting is usually not required for this test, but always follow your doctor's specific instructions.
What do the results mean?
Elevated procalcitonin levels typically suggest a bacterial infection, while lower levels may indicate a viral infection or non-infectious condition. CRP is a general marker of inflammation and can be elevated in both bacterial and viral infections, but it tends to be higher in bacterial infections. Your doctor will interpret these results together with your symptoms, physical exam, and other test results to make an accurate diagnosis.
Are there any risks?
The risks associated with this test are minimal and similar to any routine blood draw. You may experience slight bruising at the puncture site, lightheadedness, or rarely, an infection. These side effects are usually temporary and resolve quickly.
Reference range
Interpretation-based panel; results reported as bacterial likelihood score (low, moderate, high probability) combined with individual biomarker values. Procalcitonin <0.1 ng/mL suggests viral or non-bacterial etiology; 0.1-0.5 ng/mL suggests possible bacterial infection; >0.5 ng/mL suggests likely bacterial infection. CRP <10 mg/L generally viral; 10-40 mg/L equivocal; >40 mg/L suggests bacterial infection. WBC differential lymphocyte predominance suggests viral etiology.N/A
No fasting required. Specimen should be collected prior to administration of antibiotics when possible to avoid false-low procalcitonin values. Avoid collecting during or immediately after major surgery, trauma, or severe burns as these can elevate procalcitonin independent of infection.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings2
Frequently asked questions
Why do I need this test?
Do I need to fast before the test?
How long does it take to get results?
Can this test definitively tell me if I have a bacterial or viral infection?
Are there any medications that can affect the results?
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 15, 2026. · Read our editorial policy