In a population-based screening program for cervical cancer in India, which of the following is the most common cause of false-negative results in cytology-based screening?

Explanation

## Most Common Cause of False-Negative Cytology Screening **Key Point:** Sampling error and inadequate cellularity account for approximately 50–70% of false-negative results in cervical cytology screening, making it the single most common preventable source of screening failure. ### Why Sampling Error Dominates 1. **Technique-dependent**: Improper cervical sampling technique (inadequate brush pressure, wrong angle, insufficient rotation) directly reduces the number of abnormal cells collected. 2. **Specimen quality**: Inadequate cellularity (fewer than 8,000–12,000 cells) reduces the likelihood of detecting lesions, particularly early-stage disease. 3. **Anatomical factors**: Endocervical cells may be underrepresented if the transformation zone is not adequately sampled, especially in post-menopausal women or those with cervical stenosis. ### Comparison with Other Sources of False-Negatives | Source | Frequency | Preventability | |--------|-----------|----------------| | **Sampling error** | 50–70% | High (training, technique) | | Screening error (misinterpretation) | 15–25% | Moderate (QA, rescreening) | | Inflammatory obscuration | 10–15% | Moderate (repeat sampling) | | Processing artifacts | <5% | High (standardization) | **High-Yield:** The most effective way to reduce false-negatives in a screening program is to ensure adequate training of sampling personnel and implementation of quality assurance measures (e.g., repeat cytology for inadequate specimens, rescreening of negative slides). **Clinical Pearl:** In India, where cervical cancer screening is increasingly being rolled out in primary health centers, training frontline health workers on proper sampling technique is a critical intervention to improve screening sensitivity and reduce interval cancers. [cite:Park 26e Ch 10]