What is positive and negative Schiller test and when to do it
The Schiller test is a diagnostic test that consists of applying an iodine solution, Lugol, to the inner region of the vagina and the cervix and aims to verify the integrity of the cells in that region.
When the solution reacts with the cells present in the vagina and cervix and turn brown, it is said that the result is normal, however when it is unable to color a specific area, it is a sign that there is a change, requiring the performance of more specific exams.
Normally, the Schiller test is performed during colposcopy and is therefore indicated for women who are sexually active or have had abnormal results in the preventive exam, the Pap smear.
When to do the Schiller test
The Schiller test is indicated by the gynecologist for sexually active women as a routine exam, in those who present some symptom such as pain, discharge or bleeding after sexual intercourse or who have had abnormal results in the Pap smear, also known as a preventive exam.
In addition, the doctor may order the test when a gynecological disease is suspected, such as HPV, syphilis, vaginal inflammation, or cervical cancer. In these cases, in addition to performing the Schiller test, it may be necessary to perform complementary tests, such as biopsy, transvaginal ultrasound and colposcopy, for example. Learn more about the tests that can be ordered by the gynecologist.
Positive Schiller test
The Schiller test is said to be positive when, after the placement of the lugol, not all the lugol is absorbed by the tissue, and yellowed areas can be seen in the cervix, which indicates that there are changes in the cells, which may suggest the presence of benign or malignant, such as:
- IUD misplaced;
- Vaginal inflammations;
- HPV infection
- Cervical cancer.
However, the Schiller test can give a false positive result, which is why pap smear is usually requested in its place, as a way of investigating cervical cancer, because it gives clearer and more concrete results. In addition, to confirm the positivity of the Schiller test and to identify the cause of the change, the doctor may request a biopsy to show the characteristics of the tissue and cells.
Another exam similar to this is the acetic acid test where the same principle of staining of the vagina and cervix is used, in which case the region should be whitish. Where white is most evident, there are signs of cellular changes. This test is particularly suitable for women who are allergic to iodine, and therefore cannot take the Schiller test.
Negative Schiller test
The Schiller test is said to be negative when, after staining with lugol, the entire vaginal mucosa and the cervix became stained, with no yellowish regions, which indicates that there are no changes in the woman's genital region, that is, it is normal.