Does Having LSIL Mean I Have HPV?

Most people with an LSIL result on a Pap smear do have HPV, but the connection is not quite as automatic as many assume. Studies consistently find that roughly 60 to 76 percent of LSIL samples test positive for high-risk HPV strains, while the remainder either harbor low-risk HPV types that standard panels do not flag, carry viral loads too low to detect, or turn out to be mimics of LSIL caused by something else entirely. So the short answer is that LSIL is overwhelmingly driven by HPV infection, yet an LSIL result on its own does not guarantee a positive HPV test, and the distinction matters for what happens next.

How Tightly LSIL and HPV Are Linked

LSIL stands for low-grade squamous intraepithelial lesion. It describes mildly abnormal cells seen under a microscope after a Pap smear. Biologically, these changes are almost always the footprint of an HPV infection: the virus enters the surface cells of the cervix, hijacks their growth cycle, and causes the slightly enlarged, irregular-looking nuclei that a pathologist reads as LSIL. The question is not really whether HPV causes LSIL in principle; the question is how often people with an LSIL result also test positive for HPV in practice.

The numbers vary by study and by the HPV test used. A large Chinese laboratory study of more than 8,000 women with LSIL Pap results found that about 76 percent tested positive for high-risk HPV DNA.¹ A cross-sectional study from South Korea put the figure lower, at about 59 percent for high-risk types specifically.² A study of a Bengali population in India found that 75 percent of LSIL subjects tested positive for HPV.³ The spread across studies reflects differences in the specific HPV tests used, the population studied, and whether only high-risk strains were counted or all strains. But the takeaway is consistent: the large majority of LSIL cases involve HPV, usually a high-risk type.

What About the LSIL Cases That Test HPV-Negative?

If you received an LSIL result but tested negative for HPV, you are not alone, and the combination is not as contradictory as it sounds. A landmark analysis from the ALTS trial, one of the largest studies of abnormal Pap management, concluded that there was no evidence HPV-negative LSIL is its own distinct biological entity. Instead, these results appeared to represent either a misread Pap smear (the cells looked like LSIL but were actually normal or reactive) or a falsely negative HPV test.⁴

A few things can explain why HPV might not show up on a test even when it is or was present. The infection may be clearing on its own and viral levels may have dropped below the detection threshold. Some HPV tests only screen for a panel of high-risk types, so a low-risk type causing the cell changes would not register. Sampling matters too: if the swab does not collect enough cells from the affected area, the test can miss the virus. Whatever the cause, follow-up data on women with HPV-negative LSIL is reassuring. A large cohort study found that these patients had a low risk of developing high-grade lesions and no cervical cancers were diagnosed, supporting a strategy of repeat testing at one year rather than immediate further procedures.⁵

Which HPV Types Show Up Most Often in LSIL

When HPV is present in LSIL, it is not always the same strain. HPV 16, the type most strongly associated with cervical cancer, is also the single most common high-risk type found in LSIL. One study found HPV 16 in about half of women with ASCUS or LSIL who tested positive for high-risk HPV, with HPV 18 appearing in roughly 30 percent and HPV 33 in about 24 percent of those cases.⁶ Other research from China found HPV 52 and HPV 58 were common LSIL types alongside HPV 16, reflecting geographic variation in which strains circulate most.⁷

Low-risk types like HPV 6 and HPV 11, better known for causing genital warts, also turn up in LSIL. In one study they appeared in about 23 percent of LSIL cases, sometimes alongside high-risk types.⁶ The genotype matters because LSIL caused by HPV 16 or 18 carries a somewhat higher chance of progressing to a more serious lesion than LSIL caused by a lower-risk type. That is one reason current guidelines factor in which strain was detected when deciding how aggressively to follow up.

Most LSIL Goes Away on Its Own

Hearing “abnormal” on a screening result is anxiety-inducing, but LSIL is the mildest category of cervical abnormality, and the natural trajectory is strongly tilted toward resolution. The body’s immune system usually clears the underlying HPV infection and the cell changes reverse. One study tracking confirmed low-grade lesions found that about 55 percent had regressed within 12 months, and infections that were transient rather than persistent regressed completely within four years.⁸ Among young women in particular, a cohort study found that 61 percent of LSIL cases had regressed by 12 months and 91 percent by 36 months.⁹

The flip side is that roughly 10 percent of LSIL cases progress to a high-grade lesion within two years.¹⁰ That figure is why screening guidelines do not simply ignore LSIL. The immune system does the heavy lifting in most cases, but the minority that do progress need to be caught early. The key signal is whether the HPV infection persists: women whose virus clears see their cell changes normalize, while persistent high-risk HPV infection is the main driver of progression. Immune-system infiltration of the lesion by certain T cells is a hallmark of regression, which is essentially the body recognizing and destroying the infected cells.¹¹

What Happens After an LSIL Result

Clinical guidelines in the United States are risk-based, meaning your next step depends on the combination of your Pap result and your HPV result, not on either one alone. For someone aged 25 or older who was screened with cytology alone, the standard recommendation for LSIL is colposcopy, a closer visual exam of the cervix.¹² If you were co-tested (Pap plus HPV test) and both came back abnormal, colposcopy is recommended. If the LSIL came back but your HPV test was negative, guidelines support repeating both tests in one year rather than jumping to colposcopy, because the risk of a serious underlying problem is low in that scenario.

The ASCCP risk-based framework assigns clinical action based on estimated risk thresholds. If your combination of results puts your immediate risk of a high-grade lesion at 4 percent or higher, colposcopy is recommended. Below that threshold, surveillance at defined intervals is the standard approach.¹³ This is why your provider may react differently to LSIL depending on your HPV type, your age, and your screening history. An LSIL with HPV 16 in a 40-year-old prompts a faster workup than LSIL in a 26-year-old whose previous screens were normal.

When LSIL Is Not Really LSIL

Pathologists reading Pap smears do not always agree on what they see, and LSIL sits in a zone where interpretation can be subjective. A major study from the ALTS trial found only moderate agreement among pathologists interpreting Pap smears and cervical biopsies, with statistical agreement scores in the moderate range for both cytology and tissue samples.¹⁴ A more recent international study using digital whole-slide images confirmed this challenge, with only fair agreement among observers evaluating low-grade cervical lesions.¹⁵ Borderline cases with features between LSIL and HSIL are especially hard to call consistently.¹⁶

Postmenopausal women face a particular diagnostic wrinkle. As estrogen levels drop, the cervical lining thins and the cells that show up on a Pap start to look different: smaller, with proportionally larger nuclei. These atrophic cells can mimic the appearance of LSIL under the microscope, leading to over-diagnosis of abnormalities that are actually just hormonal changes. This means a postmenopausal woman receiving an LSIL result has a higher chance that it is a false alarm compared to a younger woman with the same reading. A short course of vaginal estrogen cream before repeating the Pap is sometimes used to clarify whether atrophy was the culprit.

Newer Triage Tools

Because HPV testing alone flags a lot of infections that will never progress, researchers have been developing better ways to sort out which LSIL cases need attention. One promising tool is p16/Ki-67 dual-stain cytology, which looks for two proteins that, when present together in the same cell, signal that the HPV infection is actively driving abnormal cell growth rather than just passing through. In a European trial, this dual stain detected over 94 percent of confirmed high-grade lesions among women with LSIL, while correctly sparing a larger proportion of women who did not have serious disease compared to HPV testing alone.¹⁷ A recent meta-analysis confirmed that dual staining performs well for identifying who among LSIL patients actually needs colposcopy.¹⁸ This kind of test is not yet universal, but it is increasingly available and may eventually reduce how many women with LSIL are sent for colposcopy when their lesion was always going to clear on its own.

LSIL During Pregnancy

Getting an LSIL result while pregnant can feel especially alarming, but management during pregnancy is deliberately conservative. Both the ASCCP and the International Federation of Gynecology and Obstetrics advise against treating cervical lesions during pregnancy unless invasive cancer is suspected. The standard approach is monitoring with colposcopy and cytology every 12 to 24 weeks during the pregnancy, then addressing any remaining lesion after delivery. In one case series following this approach, no cases progressed to invasive disease, and all patients underwent treatment postpartum.¹⁹ The pregnancy itself is not affected by LSIL, and the lesion does not harm the fetus.

HPV Redetection and What It Means for Partners

A common worry after an LSIL-and-HPV diagnosis is what it means for sexual partners and whether the virus keeps coming back. HPV does not behave like, say, a strep infection that is either fully cleared or not. Even after the virus becomes undetectable, the same genotype can show up again later. A long-running cohort study found that the cumulative rate of redetecting the same HPV genotype was about 7 percent at one year and about 15 percent at five years after the virus had seemingly cleared.²⁰ Whether this represents the virus reactivating from a latent state or a brand-new infection is still debated. The same study found that getting a new sexual partner was not statistically associated with redetection, which leans toward the latency explanation for at least some cases.

For partners, the practical upshot is that HPV is extremely common, most sexually active people encounter it at some point, and there is no reliable test for HPV in men outside of research settings. A partner does not need special testing or treatment based on your LSIL result. Condom use reduces but does not eliminate HPV transmission, since the virus can live on skin not covered by a condom.

Vaccination Still Helps After an LSIL Diagnosis

People sometimes assume that if they already have HPV, vaccination is pointless. The vaccine does not treat an existing infection, but it protects against other HPV types you have not yet encountered. Since most people with LSIL are infected with one or two strains at most, the vaccine can still prevent future infections with other high-risk types. Population-level data from Japan comparing pre- and post-vaccination eras found a 62 percent reduction in LSIL and more severe abnormalities among vaccinated cohorts, along with a 71 percent reduction in high-grade lesions.²¹ Current guidelines in the U.S. recommend HPV vaccination through age 26 for everyone not already vaccinated, with shared clinical decision-making for adults 27 to 45.

The Emotional Side of an Abnormal Pap

The clinical picture of LSIL is overwhelmingly reassuring, but that does not mean the emotional response is easy. Research consistently shows that receiving an abnormal Pap result triggers a range of psychological reactions, including anxiety, guilt, confusion about what the result means, and worry about future fertility or cancer risk. Women in one qualitative study described feeling uncertain about their body, powerless in the face of the result, and concerned about how the diagnosis would affect their relationships and sexuality.²² Another study found that the personal meaning people assigned to their HPV and Pap results, such as perceived stigma or risk, shaped their psychological and behavioral responses more than the clinical severity of the result itself.²³

If you are dealing with that anxiety right now, it helps to anchor yourself in what the numbers actually say: the vast majority of LSIL clears without treatment, progression to anything serious is uncommon and catches are what the follow-up schedule is designed for, and an HPV infection says almost nothing about your sexual history that could not be said about the majority of adults. The stigma around HPV vastly outweighs the medical risk of LSIL, and providers who work in this area see these results constantly. You are not an outlier.