A post on one of the CLL forums about checking your vitamin D levels convinced me to request that test from my primary doctor a few years ago. Although I felt fine, my D level was at 18.1 ng/ml.
The test was for “serum 25-OH Vitamin D” and described Vitamin D deficiency as an amount less than 20 and insufficiency as 21-29.
Since then I’ve taken 4000u daily and am back in the normal range, but still not very high.
I wear a hat with a 2” brim and avoid the sun (and live in a place with harsh winters) so don’t get much vitamin D from the sun. I have a fair complexion. I also am cautious about secondary cancers, particularly skin cancer, which has a higher incidence among CLL patients, since we have compromised immune systems.
So please add this to your routine testing. You may be deficient and not even know it!