ASC-US and HPV
Oct. 10th, 2006 09:12 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
danaerisI found some numbers on the correlation between abnormal pap smears of the ASC-US variety and HPV.
From the College of American Pathologist's CAP Today publication:
The doctors interviewed in the article were troubled by this variation, so they did a massive study comparing ASC-US with positive HPV diagnoses. They found that because the identification of ASC-US is very subjective, that the rate of correlation varied by institution by anywhere from eight to 98 per cent. So, some institutions are picky enough about what they identify as ASC-US that you can almost guarantee that if they found that you're ASC-US, you're HPV positive. Others are so UN-picky that you can near-guarantee that if you're ASC-US, you're NOT HPV positive.
They did find that the correlation between ASC-US and HPV was greater at teaching hospitals, where the staff is better trained. This could imply that a true ASC-US does mean HPV. However, your lab may not have properly diagnosed the ASC-US, so having ASC-US remains inconclusive. I imagine, that's why the 50 per cent. Because half the reporting labs do so cruddy a job that they misdiagnose one way or another.
From the College of American Pathologist's CAP Today publication:
Some studies, such as the ASC-US/LSIL Triage Study or ALTS study (J Natl Cancer Inst. 2001;93:293–299), show an HPV positivity rate for ASC-US diagnoses of 49 percent to 50 percent. “But other studies have gone as low as 41 percent,” Dr. Tworek says.
The doctors interviewed in the article were troubled by this variation, so they did a massive study comparing ASC-US with positive HPV diagnoses. They found that because the identification of ASC-US is very subjective, that the rate of correlation varied by institution by anywhere from eight to 98 per cent. So, some institutions are picky enough about what they identify as ASC-US that you can almost guarantee that if they found that you're ASC-US, you're HPV positive. Others are so UN-picky that you can near-guarantee that if you're ASC-US, you're NOT HPV positive.
They did find that the correlation between ASC-US and HPV was greater at teaching hospitals, where the staff is better trained. This could imply that a true ASC-US does mean HPV. However, your lab may not have properly diagnosed the ASC-US, so having ASC-US remains inconclusive. I imagine, that's why the 50 per cent. Because half the reporting labs do so cruddy a job that they misdiagnose one way or another.
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no subject
Date: 2006-10-11 03:54 am (UTC)Too often I find that STI's and sexual health in medicine are treated with such low importance, low precision and low priority. I wonder how much sexual health and social attitudes of doctors themselves colour the effectiveness of that reaserch and the research/pure science culture.
no subject
Date: 2006-10-11 12:35 pm (UTC)Perhaps it is just hard to diagnose ASCUS visually? When I had ASCUS, they tested for HPV as well before telling me that I had HPV. From what I understand there may be other reasons for what appears to be cell changes that are unrelated to HPV and not pre-cancerous, so it can be difficult to determine what one is looking at.
That said, it doesn't surprise me that some doctors are much less competent than others. Unfortunately, there's so much demand (at least where I live) that the bad ones don't get weeded out.