Fractional Exhaled Nitric Oxide Test
Fractional Exhaled Nitric Oxide (FeNO) Test Kits
FeNO testing measures airway inflammation by quantifying nitric oxide in exhaled breath, serving as a valuable biomarker for respiratory conditions, particularly asthma in pediatric populations.
Key Points:
- Non-invasive measure of airway inflammation
- Useful in asthma diagnosis and monitoring
- Results available in minutes
- Age-appropriate techniques available (>4 years)
- Helps guide corticosteroid therapy
Primary Indications
- Diagnostic Applications:
- Asthma diagnosis support
- Allergic airway inflammation assessment
- Distinguishing between different respiratory conditions
- Evaluation of chronic cough
- Monitoring Applications:
- Treatment response assessment
- Medication adherence evaluation
- Exacerbation risk prediction
- Long-term disease control monitoring
Specific Clinical Scenarios
- Initial Assessment:
- Unclear respiratory symptoms
- Atypical presentation
- Exercise-induced symptoms
- Allergic rhinitis with respiratory symptoms
- Treatment Decisions:
- Steroid responsiveness prediction
- Dose adjustment guidance
- Step-up/step-down therapy decisions
Testing Procedure
- Pre-Test Requirements:
- No food/drink for 1 hour prior
- No exercise for 1 hour prior
- No bronchodilator use for 4 hours
- No smoking exposure for 1 hour
- Measurement Technique:
- Online method (real-time measurement)
- Single-breath technique
- Constant flow rate (50 mL/s)
- Multiple measurements recommended
Equipment Specifications
- Device Requirements:
- Chemiluminescence analyzer
- Flow rate control system
- Visual feedback display
- Calibration system
- Quality Control:
- Daily calibration checks
- Environmental conditions monitoring
- Regular maintenance schedule
Reference Values
- Pediatric Cut-off Points:
- Low: <20 ppb
- Intermediate: 20-35 ppb
- High: >35 ppb
- Age-Specific Considerations:
- Children <12 years
- Adolescents
- Growth and development factors
Clinical Correlation
- Result Integration:
- Symptom correlation
- Lung function tests
- Clinical history
- Environmental factors
- Treatment Implications:
- Steroid response prediction
- Therapy modification guidance
- Compliance assessment
Follow-up Protocols
- Monitoring Schedule:
- Initial diagnosis: baseline measurement
- Treatment initiation: 4-8 weeks
- Stable patients: 3-6 months
- Exacerbations: as needed
- Clinical Decision Points:
- >20% change considered significant
- Trend analysis importance
- Integration with other parameters
Documentation Requirements
- Essential Elements:
- Test conditions
- Technical factors
- Patient cooperation
- Result validity assessment
Technical Considerations
- Test Performance Factors:
- Proper breathing technique required
- Age limitations (typically >4 years)
- Cooperation requirements
- Environmental influences
- Confounding Factors:
- Recent respiratory infections
- Dietary factors (nitrate-rich foods)
- Exercise
- Medications
Clinical Limitations
- Diagnostic Considerations:
- Not a standalone test
- Variable in viral infections
- Cost implications
- Availability limitations
- Special Populations:
- Very young children
- Severe respiratory distress
- Cognitive impairment
