It is quite common for labs to have different reference ranges. It really does not matter in terms of diagnosing and monitoring a MPN. Based on the WHO diagnostic criteria, thombocytosis = PLT > 450 [10^3/uL]. The

Great question
I believe what matters is how you feel

Please explain your question. 1) What are the other ranges UCLA and Cedars gives? 2) its a range, but all labs have a CONTROL which may make their numbers slightly different. like in school we always were told normal platelets were 150-450K. But it truly depends on the lab, but should be close. I would be concerned if they were talking millions as normals, but they wont. The numbers are relative.

Most cancer centers in the U.S. use 450 as the top number. I don't know why UCLA uses a much lower number for top of the range, or why my hematologist there was so focused on bringing my platelets into UCLA's range. My new hematologist is at Cedars Sinai, which is also a top-rated Med Center. He says there is "no data" to show that keeping blood platelets in normal range is necessary. What's important is to keep them at a non-dangerous level. He is satisfied with my current platelet counts in the 400's, as they were in 700's when I treatment started 3.5 years ago. He also has me gradually phasing in Anagrelide and taking less HU, due to my side effect problems with HU. My digestive issues have already improved. I'm looking forward to feeling better in 2024 than I did throughout 2023, when HU was increased to taking two capsules on some days. Happy New Year!

It mattered to my former hematologist, as his focus was on bringing my platelets into normal level based on the much lower normal level used at UCLA. I've switched to a Cedars Sinai MPN specialist who has a more modern, more flexible approach.