1. Test Sensitivity: If a test has lower sensitivity, it may miss detecting the disease in some individuals. 2. Timing of the Test: The stage of infection or disease can affect the test results. For example, testing too early in the course of an infection might not detect the presence of pathogens. 3. Human Error: Mistakes in sample collection, handling, or processing can lead to false negatives. 4. Technical Limitations: Some tests may not be able to detect all strains or types of a pathogen.
