Colonoscopy & ITP

Time for me to have a colonoscopy.
While it's not my first one, I am very apprehensive this time. Previously, my colonoscopy was performed by a private doctor in consultation with my hematologist. I also met with the gastro-enterologist prior to the col.
Right now I am receiving all my medical care at a public hospital. I will not see my hematologist for a few weeks (Oct) and plan to schedule the procedure for shortly after, depending on my platelet count. I am taking 75mg of Promacta and my count is usually 45-55.
My questions are:
Under which circumstances is a colonoscopy not advised, i.e. what are the risks? What is the minimum Platelet count for a safe colonoscopy?
Thank you!

Here is one opinion, from the British Columbia Medical Journal 2005.
50k is a number we hear very often.

For patients undergoing surgery and invasive procedures
www.bcmj.org/article/proposed-guidelines-platelet-transfusion
Expert consensus and retrospective case series suggest that a platelet count of >50 x 109/L is sufficient for most invasive procedures, including gastroscopy and biopsy, insertion of indwelling lines, transbronchial biopsy, liver biopsy, laparotomy, or similar procedures.[4,6,7] Platelet counts >100 x 109/L are recommended for neurosurgery or ocular surgery.[4]

For adults and children, most experts recommend platelet counts of >50 x 109/L prior to lumbar puncture as platelet counts <20 x 109/L have been associated with increased risk of hematoma or traumatic tap. No clear minimum platelet count has been identified for the insertion of epidural catheters, with published recommendations ranging from >50 x 80 x 109/L.[4,10,11]

Vaginal delivery can be performed safely with maternal platelet counts >50 x 109/L,[12] as hemostasis after placental separation is largely mechanical.

Bone marrow biopsy can be performed safely without platelet support if adequate surface pressure is applied.[4]

If you mention you have platelet problems they might overreact and make you get the test in a hospital even if your counts are fine. Check with your Hemo on what count is advisable, and get a count the day before the procedure. If you are dangerously low then a hospital setting is smart.
Erica