The following are some factors that may affect the accuracy of HPV sampling:

Factors before Sampling

• Patient Preparation
  • Menstrual Cycle: Sampling during menstruation may be interfered with by menstrual blood, affecting the accuracy of the test results. It is generally recommended to perform sampling 3-7 days after menstruation ends.
  • Vaginal Medication: Using vaginal suppositories, gels, and other medications before sampling may change the environment inside the vagina and affect the distribution of the HPV virus. Or the medications themselves may cover the surface of the cells, making it impossible to accurately detect the virus. Usually, sampling should be carried out at least 48 hours after stopping the medication.
  • Sexual Intercourse: Having sexual intercourse within 24 hours before sampling may introduce substances such as semen and condom residues, interfering with the sample. Moreover, sexual intercourse may change the microenvironment of the vagina and cervix, affecting the detection of HPV.
• Sampling Time
  • Infection Duration: After the human body is infected with HPV, there is a certain incubation period. The viral load may be relatively low during the incubation period, and the virus may not be detected during sampling at this time. It is generally recommended to wait at least 2-3 weeks after a suspected infection before sampling.
  • Disease Progression Stage: At different stages of HPV-related diseases, the distribution and content of the virus in the diseased tissues may vary. For example, in the early stages of cervical precancerous lesions or cervical cancer, multiple samplings or sampling at specific sites may be required to accurately detect HPV.

Factors during Sampling

• Sampling Site
  • Sampling Depth: In the case of cervical sampling, if the sampling brush does not penetrate deep into the squamocolumnar junction area of the cervical canal, it may miss the site where the HPV virus is likely to infect, resulting in false negative results.
  • Multiple-point Sampling: HPV infections may be focally distributed, and single-point sampling may miss the infected site. Therefore, for some high-risk groups or patients with a suspected large range of lesions, multiple-point sampling may be necessary.
• Sampling Technique
  • Sampling Force: If the sampling force is too small, it may not be possible to collect enough cells and viruses. If the force is too large, it may cause tissue damage and bleeding, and the components in the blood may interfere with the detection.
  • Sampling Method: Different sampling methods may affect the sampling effect. For example, rotational sampling may collect more cells and viruses than wiping sampling.

Factors after Sampling

• Sample Preservation
  • Preservation Temperature: HPV samples need to be preserved at a specific temperature, generally between 4°C and 8°C. Excessively high or low temperatures may lead to the degradation of viral nucleic acids, affecting the test results.
  • Preservation Duration: If the sample is preserved for too long, the viral nucleic acids will gradually degrade. It is generally recommended to send the sample for inspection as soon as possible after sampling, and the preservation time should not exceed 24 hours.
• Transportation Process
  • Vibration: Excessive vibration during transportation may damage the cell structure in the sample, affecting the detection of the virus.
  • Change in Preservation Conditions: If the preservation temperature, humidity, and other conditions change during transportation, it may lead to a decline in the quality of the sample.

Factors of the Detection Method

• Detection Technology: Different HPV detection technologies, such as the PCR method and the hybrid capture method, have different sensitivities and specificities. Choosing an inappropriate detection method or the limitations of the detection technology itself may affect the accuracy of the test results.
• Detection Reagent: Factors such as the quality of the detection reagent and the differences between batches will also have an impact on the test results. Low-quality reagents may have false positive or false negative results.