Hi newMNer
The time taken for borderline changes to resolve can vary depending on the cause. Causes can include: infections such as Candida, hormonal changes such as being post-natal, using IUCD or depo-provera contraception, sometimes its because the cells weren't very well preserved and were tricky to interpret, so the cytologist may have been working on the cautious side and wanted to get a repeat test.
Sometimes HPV infection is the cause of a borderline result. Most people have had HPV at some point in their life, and the immune system deals with it, the time taken to clear it varies but it can take up to 24 months from what I've read. So if a woman has a cervical sample taken during that time, it will probably show some changes in the cells but it will go away without treatment. From a cytologist's POV we can't tell what stage the infection's at, all we can see is the changes it causes in the cells. So we can also see when it's no longer active. See my post above (of Fri 17-Apr-09 23:48:38)
The follow-up tests are usually three repeats over a period of 18 months, usually 6 months apart. Sometimes women will have a couple of tests with low grade changes, a year apart and then go back to normal afterwards.
The letters you've received about cervical screening, did they come from 'call/recall', 'screening services' or the PCT - they will usually be on the behalf of your GP these days. Some areas still have the GP/surgery send out the letters.
The reminder letter may have been produced before the result of your test got entered onto the system as the test result is sent from the lab to the PCT database who send the invite/reminder/result letters. The surgery may also contact you with reminders as well.
Here is an outline of the Cervical screening process, my post on 12/10/09 at 21:59.
It might be worth checking with your practice that they have a copy of your test result as well, to ensure their records have been updated.
At any point, if you have any pain, discomfort or unusual bleeding then you should see a GP. If your follow-up test in six months time shows low grade changes again, then usually you would be referred to colposcopy. The guidelines say no more than 3 low grades in a 10 year period, even if you have been returned to normal recall.
HTH