Dear Joan,

I was very impressed recently to read that you had taken the trouble to calculate the molecular weight of 17 OHP in order to find the right conversion to nmol/L....now THAT's dedication!!  I, too, had been frustrated by not knowing how to convert to/from this unit.

I thought you might be interested to know that I actually came across an "official" formula recently, in some book I  was skimming.  It gives the conversion as follows:

200 mg/dl=11.1 mmol/L

I haven't bothered yet to correlate it to ng/dl; nmol/L; ng/ml; or any of that good stuff, but thought you might find this useful!