VIA, VILI and Cervical Screening in India
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Direct answer
VIA and VILI are low-cost visual inspection tests for cervical cancer screening, using acetic acid or Lugol iodine applied to the cervix. A positive VIA shows a dense, well-defined aceto-white area, while a positive VILI shows an area that fails to stain. Both are used in India's primary care programme because they need no laboratory, and positive women are treated or referred under a screen-and-treat algorithm.
What you must remember
- VIA: Visual inspection with 3 to 5 per cent acetic acid, where a dense aceto-white lesion with well-defined margins is positive.
- VILI: Visual inspection with Lugol iodine, where normal squamous epithelium stains mahogany brown and an unstained area is positive.
- Cytology: The Pap smear needs laboratory infrastructure and trained cytopathologists, so it is harder to deliver in camps.
- HPV testing: Detects high-risk HPV DNA, is more sensitive than visual tests, and is the WHO-recommended primary screening method where available.
- WHO target: Screening 70 per cent of women with a high-performance test by ages 35 and 45.
- Eligibility in India: Women aged 30 years and above under the national non-communicable disease screening programme.
- Positive result: Eligible women are treated on the spot with cryotherapy or thermal ablation, and others are referred for colposcopy.
A screen-and-treat algorithm for a primary health centre
A 42-year-old attends a screening camp for the first time. The algorithm below applies to her. Visual tests are used because the camp has no cytology laboratory.
- Eligibility and counselling: Screen women aged 30 years and above, explaining the test and what the result means before the examination.
- Perform the visual test: Apply 3 to 5 per cent acetic acid, or Lugol iodine where that is the programme choice, and inspect the cervix under good light.
- Interpret the result: Record a negative result and schedule rescreening at the interval set by programme guidance, commonly several years later.
- Treat eligible positives: A positive test with a fully visible transformation zone and no suspicion of cancer is treated by cryotherapy or thermal ablation at the same visit.
- Refer the rest: Positive women who are not eligible for ablation, and any suspicious growth, are referred to colposcopy, and suspected invasive cancer is referred urgently.
Records of each screened woman allow the programme to track referrals and follow-up.
Where the exam tries to catch you
Screening questions test the logic of the algorithm more than the chemistry of the tests.
- Trap: Treating every VIA-positive woman with cryotherapy at the first visit Correct: Ablation is limited to lesions that fit the criteria and a fully visible transformation zone, and others go to colposcopy.
- Trap: Calling a VILI-positive area proof of cancer Correct: An unstained area is a screen-positive finding that needs assessment, not a diagnosis.
- Trap: Choosing cytology as the first screen in a rural camp Correct: Visual tests need no laboratory and suit resource-limited programmes, while HPV testing is preferred where feasible.
Frequently asked questions
What is a positive result on visual inspection with acetic acid?
A positive VIA is a dense, well-defined aceto-white area on the cervix after application of 3 to 5 per cent acetic acid. It indicates a possible precancerous lesion that needs further action. Positive VIA results are then treated or referred under the screen-and-treat algorithm.
Why is VILI sometimes preferred over VIA?
Pooled studies suggest VILI is more sensitive than VIA with similar specificity, because normal squamous epithelium takes up the iodine and the unstained area is easier to define. Its positive result is an unstained area on a brown background. The choice between the two depends on the programme and local training.
What is the screening age and interval in the Indian programme?
The Indian national programme screens women aged 30 years and above for cervical cancer using visual tests. Repeat screening intervals follow current programme guidance and are commonly set at several years after a negative test. Women with positive tests follow a separate pathway.
Which test does WHO recommend as primary cervical screening?
WHO recommends high-risk HPV testing as the primary screening method where it is available. The WHO target is for 70 per cent of women to be screened with a high-performance test by ages 35 and 45. Visual tests are acceptable alternatives in resource-limited settings.
When should a woman with a positive visual test be referred for colposcopy?
A woman with a positive visual test should be referred for colposcopy when she is not eligible for thermal or cryotherapy ablation, or when the lesion looks suspicious. Suspected invasive cancer needs urgent referral regardless of eligibility. Colposcopy-directed biopsy then establishes the histology.