What factors affect the accuracy of cervical screening?

What factors affect the accuracy of cervical screening?

Test time
Menstrual factors: Cervical screening during menstruation can affect accuracy. Because menstrual blood flows out, it may dilute the cell components in the cervical secretions, and the presence of blood can interfere with the observation of cervical cell morphology. For example, in a cervical smear test, blood may mask abnormal cells and lead to false negative results. In addition, the cervical opening of menstruating women is in a relatively open state, and testing at this time also increases the risk of infection.

Sexual time: Having sex within a short period of time before the test can affect the test results. Sexual activity may cause damage to the cervical mucosa and cause non-disease-related morphological changes in cervical cells. At the same time, semen will remain in the vagina, and the components in semen may affect the detection of cervical cells and pathogens. It is generally recommended to avoid sexual intercourse 2-3 days before cervical screening.

Sampling operation
Sampling site: Cervical screening requires the collection of cells from the cervical opening and cervical canal. If a sufficient number of diseased cells are not collected during sampling, a false negative result will occur. For example, for lesions in the cervical canal that are deep in the lesion, if the sampler does not penetrate deep enough, the lesion cells may be missed. Moreover, the sampling range should include the cervical squamous-columnar junction, which is a common site for cervical precancerous lesions and cervical cancer. If the sampling is not in place, the accuracy will be greatly reduced.
Sampling tools and methods: Inappropriate sampling tools or incorrect sampling methods will also affect the accuracy. For example, if the material of the cervical brush is too hard, it may damage the cervical tissue, cause bleeding, and affect the cell morphology; and if the force is too large or too small during sampling, it is not appropriate. Too much force may damage the cervix, and too little force may not collect enough cells.

Sample processing and testing
Sample preservation and transportation: If the collected samples are not properly preserved, such as not placed in a suitable preservation solution or the preservation temperature is not appropriate, the cells may degenerate, necrotize, etc. During transportation, if the samples are subjected to severe vibration, too high or too low temperature, etc., it will also affect the integrity of the cells and the activity of the detection markers. For example, if the HPV test samples are placed in a high temperature environment for a long time, the nucleic acid of the virus may degrade, resulting in inaccurate test results.
Detection technology and reagents: Different detection technologies and reagents also affect the accuracy of cervical screening. Advanced detection technologies, such as HPV detection methods based on genotyping, can more accurately detect specific subtypes of high-risk HPV and improve the accuracy of diagnosis. Poor-quality detection reagents may produce false positive or false negative results. For example, some low-quality cervical cytology detection reagents may not be able to identify abnormal cell morphology well and misjudge precancerous cells as normal cells.

Individual factors
Cervical inflammation and other lesions: When there is inflammation in the cervix, inflammatory cells will be mixed with cervical epithelial cells, interfering with the observation and judgment of cervical cells. For example, in cervicitis, the cervical mucosa is congested and edematous, with a large number of inflammatory cells infiltrating. In cervical smear examinations, inflammatory cells may mask the cells of cervical intraepithelial neoplasia. In addition, other lesions such as cervical polyps and cervical condyloma acuminatum will also affect the accuracy of cervical screening.
Physiological state and hormone levels: Changes in women’s physiological state and hormone levels will also affect cervical screening results. For example, during pregnancy, cervical tissue undergoes a series of changes due to hormones, such as thickening of the cervical mucosa and eversion of the columnar epithelium. These changes may cause cervical cells to undergo morphological changes similar to lesions, increasing the difficulty of judgment. Cervical atrophy in postmenopausal women may also affect the accuracy of sampling and the judgment of cell morphology.