Fluid For Culture & Sensitivity (Radiometric)
- Sample Type
- Body Fluid
- Fasting
- No
- Unit
- N/A
Function
A Culture and Sensitivity (C&S) test of body fluids (such as pleural, peritoneal, pericardial, or synovial fluid) is designed to identify the presence of pathogenic microorganisms. The 'Radiometric' method refers to an automated system that detects carbon dioxide produced by metabolizing bacteria using radioactive isotopes or sensitive infrared sensors, allowing for faster detection than traditional visual methods.
Why it is Ordered
This test is critical when a clinician suspects an infection in a sterile body cavity. It is ordered to:
- Diagnose bacterial, fungal, or mycobacterial infections.
- Determine the most effective antibiotic treatment (Sensitivity testing).
- Differentiate between infectious and non-infectious causes of fluid accumulation (effusions).
- Monitor the effectiveness of ongoing antimicrobial therapy.
Associated Conditions
Specific conditions identified through this test include:
- Septic Arthritis: Infection in a joint space.
- Peritonitis: Infection of the abdominal lining, often following a ruptured organ.
- Pleural Empyema: A collection of pus in the space between the lung and chest wall.
- Meningitis: If the fluid is cerebrospinal (CSF).
- Bacteremia: When the source of systemic infection is localized to a specific fluid compartment.
Why Context Matters
The primary confounding factor for fluid cultures is the prior administration of antibiotics, which can inhibit the growth of bacteria in the lab and lead to a false-negative result (partially treated infection). Additionally, skin contaminants (like Staphylococcus epidermidis) can be introduced during the aspiration process, leading to false positives. Interpretation requires correlation with fluid white blood cell counts and clinical symptoms.
Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.
Clinical References
Source-of-truth databases and clinical guidelines for Fluid For Culture & Sensitivity (Radiometric):
Official Sources
Research & Guidelines
Related Indicators
Medically Reviewed by Dr. Binoy Babu, MBBS
Board Certified Doctor • 10+ Years Clinical Experience
Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.
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