HPV 16 and 18 Positive: What Does Genotyping Mean?
The difference between HPV 16/18 and other high-risk types on an HPV test: what genotyping is, whether colposcopy is needed with a normal smear, and how follow-up works.
If your HPV test is positive and the report says "16/18," that detail changes your follow-up plan. HPV 16 and 18 are the two types that carry the higher risk of causing cervical cancer, so even if the smear result is normal, evaluating the cervix with colposcopy (a close look with a magnifying instrument) is usually recommended. With other high-risk types, repeating the test after about a year is often enough. This article explains what genotyping (telling the virus types apart) is, how to read the report and how follow-up proceeds. For the broader picture, see our page on HPV testing, vaccination and follow-up of a positive result and our page on the smear test and HPV test.
What Is Genotyping?
HPV is not a single virus but a group of many types. The high-risk group looked for in cervical cancer screening has 14 types: 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68. Genotyping means that the test reports which type the positive virus is, individually.
Most tests in use today perform partial genotyping:
- HPV 16 and HPV 18 are reported separately.
- The remaining 12 high-risk types are reported together under one "other high-risk types" heading, as positive or negative as a group.
So on the report you may see wording such as "16 positive," "18 positive" or "other high-risk types positive."
Why Are 16 and 18 Assessed Separately?
Not all high-risk types carry the same risk:
- HPV 16 and 18 are responsible for about 70% of cervical cancers. HPV 16 alone accounts for about half. HPV 18 stands out especially in cancers arising from the glandular tissue of the cervical canal (adenocarcinoma) and in faster-growing cancers.
- These two types disrupt the cell's protective mechanisms against cancer (the p53 and Rb genes) more strongly. Pre-cancerous changes (CIN 2 and CIN 3, meaning moderate and advanced cell abnormalities) are therefore more likely to develop.
- Other high-risk types (31, 33, 45, 52, 58 and others) can also cause cell changes. However, the immune system clears them more easily, and the risk of progression to advanced change is clearly lower.
How Is Follow-Up Done?
The follow-up decision depends on the type of the positive virus and the smear result. The general approach in international guidelines is:
- HPV 16 or 18 positive: Even if the smear is normal (NILM), colposcopy is generally recommended. A smear evaluates only surface cells, so a change in the background can be missed.
- Another high-risk type positive and a normal smear: Colposcopy is generally not needed right away. The smear and HPV test are repeated together after about 1 year (called "co-testing").
- At the one-year check, if HPV is still positive or the smear shows a cell abnormality, you are referred for colposcopy. If the virus has cleared and the smear is clean, you return to the routine screening interval.
If the smear also shows an abnormality, the plan is different; see our article on abnormal smear results. Age, previous results and pregnancy can change the plan; the examining doctor determines the exact roadmap.
What Does Colposcopy Involve?
Colposcopy is a procedure done on the examination table in which the cervix is examined closely with a lit magnifying instrument. If an area looks suspicious, a small piece of tissue (biopsy) may be taken. Being referred for colposcopy does not mean you have cancer; the aim is to catch any pre-cancerous change early. We explained how the procedure is done in what is colposcopy and what may follow in what to expect after colposcopy and biopsy.
Outcomes of any surgical or interventional procedure vary from person to person. It is recommended that you get detailed advice from your doctor before the procedure.
Why Are HPV 6 and 11 Not on the Report?
The low-risk types HPV 6 and 11 are responsible for most genital warts and mild surface tissue changes. They do not cause cervical cancer. Because the purpose of screening is to catch pre-cancerous changes, these types, which cannot cause cancer, are not looked for in screening tests. Otherwise, infections that mostly clear on their own would lead to unnecessary biopsies, treatment and anxiety. Genital warts need a separate assessment; see our article on genital warts.
Frequently Asked Questions
I am HPV 16 positive. Do I have cancer?
No. HPV 16 positivity does not mean you have cancer; it shows the presence of the virus. The cancer risk rises when the virus stays in the body for years. That is why monitoring and, if needed, colposcopy are planned.
HPV 16/18 positive but my smear is clean. Is colposcopy still necessary?
Guidelines generally recommend colposcopy in this situation because a smear cannot catch every change. Your doctor makes the final decision based on your age and history.
Does the genotyping result determine treatment?
Genotyping determines not treatment but the frequency of follow-up and whether colposcopy is needed. There is no medicine for the virus itself; the body often clears the infection on its own. HPV vaccination and regular screening protect; see our article on the HPV vaccine.
Which result is called "positive"?
The screening test is positive when any of the 14 high-risk types is found. For what to do after a positive result, see our article on what to do if HPV is positive.